Never Home Alone

From Microbes to Millipedes, Camel Crickets, and Honeybees, the Natural History of Where We Live


By Rob Dunn

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A natural history of the wilderness in our homes, from the microbes in our showers to the crickets in our basements

Even when the floors are sparkling clean and the house seems silent, our domestic domain is wild beyond imagination. In Never Home Alone, biologist Rob Dunn introduces us to the nearly 200,000 species living with us in our own homes, from the Egyptian meal moths in our cupboards and camel crickets in our basements to the lactobacillus lounging on our kitchen counters. You are not alone. Yet, as we obsess over sterilizing our homes and separating our spaces from nature, we are unwittingly cultivating an entirely new playground for evolution. These changes are reshaping the organisms that live with us — prompting some to become more dangerous, while undermining those species that benefit our bodies or help us keep more threatening organisms at bay. No one who reads this engrossing, revelatory book will look at their homes in the same way again.




My work, which I’ve done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men. And therewithal, whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof.

—ANTONY VAN LEEUWENHOEK, in a letter dated June 12, 1716

THERE IS NO singular origin story of the study of the wilderness of life in homes, but a day in Delft in 1676 comes close. Antony van Leeuwenhoek had walked the block and a half from his house to the market to buy black pepper. He strolled past the fish market, the butcher, and the town hall. He paid for the pepper, thanked the vendor, and then returned home. Once home, Leeuwenhoek did not sprinkle the pepper in his food. Instead, he carefully added a third of an ounce of the black stuff to a teacup filled with water. He then let the water and pepper steep. He was trying to soften the peppercorns so he could break them open and, in doing so, discover what it was inside them that led them to be spicy. Over the coming weeks, he checked on the peppercorns again and again. Then, after about three weeks, he made what was to prove a pivotal decision. He decided to draw a sample of the pepper water itself up into a thin tube of glass he had blown. The water seemed surprisingly cloudy. He examined it through a kind of microscope, a single lens affixed to a metal frame. This setup worked well for translucent things, such as pepper water, or for the thin sections of solid materials he would later teach himself to make.1

When Leeuwenhoek looked through his lens at the pepper water, he saw something unusual. Figuring out just what it was took some fidgeting and finessing. He either moved his candle this way and that, if working at night, or maybe he moved himself this way and that, if he was working using light from his window. He tried multiple samples. Then, on April 24, 1676, he finally had a clear view. What he saw was truly special: “an incredible number of very little animals of diverse kinds,” as he put it. He had seen microscopic life before, but never anything quite so small. He would repeat this procedure in various permutations a week later, then again, then again with ground pepper, then with pepper in rainwater, then with other spices, each substance infused in his teacup. Each time he did this, he saw ever more life. These were the first sightings of bacteria by a human. And they were sightings being made in a home while studying materials that can be found in any kitchen, black pepper and water. Leeuwenhoek was at the edge of the wilderness, the miniature wilderness of his own home. He had seen a dimension of this living world that had never been seen before. The question remained whether anyone would believe what he had seen.

Leeuwenhoek probably started using microscopes to study the life around him, in his home and beyond, a decade prior in 1667. The moment when Leeuwenhoek saw bacteria in pepper water came only after hundreds, maybe thousands, of hours spent searching his home and daily life more generally. Chance does, indeed, favor the prepared mind, but it favors the obsessed mind even more. Obsession comes to scientists naturally enough. It emerges when one mixes focus and relentless curiosity. It can strike anyone.

Leeuwenhoek was not a scientist in the traditional sense. By trade, he worked with fabrics and sold cloth, buttons, and other related bits and pieces out of a shop in his home in Delft.2 Leeuwenhoek likely began to use lenses of some kind to inspect the fine threads of particular fabrics.3 But something then motivated him to explore other things in his home. It may have been a book published by Robert Hooke, Micrographia.4 Leeuwenhoek spoke only Dutch, so he would have been unable to read Hooke’s text, but the pictures of what Hooke had seen through his own microscope could have been inspiration enough.5 From what we know of Leeuwenhoek’s personality, it is easy to imagine him, after having seen the pictures, using the first Dutch-English dictionary (published in 1648) to puzzle through paragraph after paragraph of Hooke’s words.

By the time Leeuwenhoek started to look through his microscope, other scientists had already used microscopes to see new details of home-dwelling creatures. Those scientists, including Hooke, found previously unsuspected patterns in life’s interstices, patterns that suggested a world beyond that which was known. A flea’s leg, a fly’s eye, and the long-stalked spore cases (sporangia) of the fungus Mucor growing on a book cover in Hooke’s home, all revealed minutiae not previously seen, or even imagined. We can examine the same species today, using the same magnification, but when we do our experience is very different from what it would have been in the 1600s. We already know that microscopic details exist even if we are surprised when we encounter them firsthand. For the scientists working in the early days of microscopy, the experience was more surprising, akin to discovering secret messages scrawled across each surface of the living world, messages no one else had ever seen.

As Leeuwenhoek peered through microscopes at the life in and around his home, he, too, saw new details. He saw the flea, for example, and drew many of the details that Hooke had drawn, but he also saw things Hooke had missed. He saw the flea’s seminal vesicles, each no larger than a sand grain. He even saw the flea’s sperm inside those vesicles, which he then compared to his own sperm.6 As he continued to search, he began to notice entire life-forms that had never before been seen, life-forms entirely invisible without a microscope. These weren’t overlooked details; Leeuwenhoek had found something more significant: he had discovered what we now call protists, a grab bag of single-celled life-forms united only by their size. They divided. They moved. And there were many kinds, some larger, some smaller, some hairy, some smooth, some with tails, some without, some attached to surfaces, and others unmoored.

Leeuwenhoek told people he knew in Delft about his discoveries. He had many friends, be they fishmongers, surgeons, anatomists, or nobles. One of those friends was Regnier de Graaf, who lived not far from Leeuwenhoek. De Graaf was a young man and yet already very accomplished. By the time he was thirty-two, he had discovered, for example, the function of the fallopian tubes. Leeuwenhoek’s discoveries made such an impression on de Graaf that on April 28, 1673, he sent a letter to Henry Oldenburg, the secretary of the Royal Society in London, on Leeuwenhoek’s behalf, despite the fact that he was mourning the death of a newborn child. In the letter, de Graaf noted that Leeuwenhoek had amazing microscopes and urged Oldenburg and the Royal Society to give Leeuwenhoek some specific assignments to pursue, subjects on which to focus with his microscope and skill. De Graaf also enclosed some of Leeuwenhoek’s notes about his discoveries.

Upon receiving the letter, Oldenburg wrote back directly to Leeuwenhoek and asked him for figures to accompany his descriptions.7 In August, Leeuwenhoek responded (by which time de Graaf had tragically died), adding more details about the things he had seen but that others (including Hooke) had missed: the physical appearance of mold, the stinger of a bee, the head of the bee, the eye of the bee, the body of a louse. Meanwhile, Leeuwenhoek’s first letter, the letter that de Graaf had shared on his behalf, was published on May 19 in the Philosophical Transactions of the Royal Society, the second oldest scientific journal in the world, at that time still in just its eighth year. This was to be the first of many letters, letters akin to what one might now find in a blog post. The letters were not heavily edited; nor were they always structured. They were often digressive and repetitive. But these daily observations of the small things in his house and town were novel; they were observations of scenes no one had ever seen before. It was in one of these letters, sent on October 9, 1676, letter eighteen, that Leeuwenhoek recorded his observations about the pepper water.8

LEEUWENHOEK SAW PROTISTS in the pepper water. Protists include many kinds of single-celled organisms, each more closely related to animals, plants, or fungi than to bacteria. Leeuwenhoek described what appear to have been protist species of the bacteria-feeding genera Bodo, Cyclidium, and Vorticella. Bodo has a long whip-like tail (flagellum), Cyclidium is covered with wiggling hairs (cilia), and Vorticella attaches itself to surfaces by a stalk (and filters water for food). But then he also spotted something else. The smallest of the organisms in the pepper water were, he calculated, one one-hundredth the width of a grain of sand and one-millionth the volume. In retrospect, we know something so small could only be a bacterium. But in 1676, bacteria had never been seen by humans before; this was their grand reveal. Leeuwenhoek was thrilled, as he was quick to note to the Royal Society,

this was among all the marvels that I have discovered in nature the most marvelous of all, and I must say that, for my part, no more pleasant sight has yet met my eye than this of so many thousands of living creatures in one small drop of water, all huddling and moving, but each creature having its own motion.9

The Royal Society had been pleased with Leeuwenhoek’s first seventeen letters. However, with the letter on pepper water, he had finally gone too far, strayed from the path of truth toward that of pure imagination. Robert Hooke in particular balked. Hooke, thanks to the success of Micrographia, was the acknowledged king of the microscopic and had never seen anything so small alive. Hooke and another well-established member of the Royal Society, Nehemiah Grew, proceeded to try to repeat Leeuwenhoek’s observations with an eye toward proving them false. It was part of what the society did, stage and repeat experiments. Usually they were done as simple demonstrations. In this case, however, the experiment was undertaken both as a demonstration and to determine whether or not the results Leeuwenhoek reported were true.

Figure 1.1 Various life-forms and particles observed by Leeuwenhoek under his microscopes, drawn to scale relative to the period at the end of this sentence. (Figure by Neil McCoy.)

NEHEMIAH GREW WAS the first to try to repeat Leeuwenhoek’s observations. He failed. Hooke took it upon himself to try. Hooke repeated each of the steps Leeuwenhoek took with the pepper, water, and microscope and he saw nothing. He grumbled. He scoffed. But he also tried again. He tried harder. He made better microscopes. On his third attempt, he and ultimately the other members of the Royal Society began, finally, to see some of what Leeuwenhoek had seen. In the meantime, Leeuwenhoek’s pepper water letter, which had been translated into English by Oldenburg, was published by the Royal Society. With the publication of this letter, and the confirmation of Leeuwenhoek’s observations by the Royal Society, the scientific study of bacteria—bacteriology—began. Notably, it began with the study of a bacterium found in a mix of ordinary kitchen pepper and water, a bacterium found indoors.

Three years later, Leeuwenhoek repeated the pepper experiment, but this time he kept the pepper water in a sealed tube. In the tube, the bacteria used up the oxygen that was present and yet something continued to grow, and bubble. Leeuwenhoek had once again discovered something new with the pepper water, this time the existence of anaerobic bacteria, bacteria able to grow and divide without oxygen. He once again made this new discovery while studying the life in his own home. The study of bacteria in general and the study of anaerobic bacteria in particular both began with the study of the life in a house.

We now know that bacteria are everywhere—in places with and without oxygen, in hot places and cold places, in every place—a layer, sometimes thin and sometimes thick, of life on each and every surface, inside each and every body, in the air, in the clouds, and at the bottom of the sea. Tens of thousands of bacterial species have been identified and millions (perhaps trillions) of other species are thought to exist. But in 1677, the bacteria Leeuwenhoek and a few members of the Royal Society had discovered were the only bacteria known in the world.

LEEUWENHOEK’S WORK IS sometimes discussed, both historically and today, as though the man simply used a new tool to study the world around him and, in doing so, revealed new worlds. In this telling, the story is all about the microscope and its lens. The reality is more complex. Today, you can fasten a microscope of the same magnification as Leeuwenhoek used to your camera. (And you should.) If you do, you can use it to search around your house, but you will not see the world the way Leeuwenhoek did. Leeuwenhoek’s discoveries did not result simply because he possessed a diversity of very good microscopes with well-made lenses. The discoveries depended on his patience, persistence, and technical abilities. It wasn’t the microscopes that were magical but rather the combination of the microscopes and his careful hands and wonder-filled mind.

Leeuwenhoek was better at seeing this world, in all its grandeur, than anyone else. But doing so took work that others considered to be impossibly hard. So the members of the Royal Society, despite having seen the world Leeuwenhoek discovered, failed to continue to study it in any real earnestness. After verifying Leeuwenhoek’s observations of microbes, Hooke continued to look at microscopic life through his own microscopes for about six months. But then he was done. Hooke and other scientists left the new world to Leeuwenhoek. Leeuwenhoek was to become an astronaut of the miniature, all alone exploring a realm that was more diverse and elaborate than anyone but him seemed to understand.

For the next five decades of his life, Leeuwenhoek systematically documented each and every thing around him; he documented all of Delft and beyond (often through samples brought to him by friends), but especially the living contents of his house. Anything he stumbled across was fair game. He studied the water in gutters, the water in rain, the water in snow. He detected microbes in his own mouth, and then in his neighbor’s mouth. He observed living sperm (again and again) and showed how it varied among species. He showed that maggots arose from the eggs of flies rather than spontaneously from filth. He documented, for the first time, a kind of wasp that lays its eggs inside the bodies of aphids. He noticed, for the first time, that adult wasps survive the winter by slowing down and going quiescent. Over his years of dedicated study, he saw many kinds of protists for the first time, the first storage vacuoles,10 the banded patterns in muscles. He discovered organisms living in the rind of cheese, in wheat flour, everywhere. He searched, he saw, he wondered, he discovered, again and again and again throughout the fifty years of his ninety-year life. He was like Galileo, dumbfounded and inspired. But whereas Galileo had to satisfy himself with looking out at the universe and the movements of stars and planets as tests of his predictions, Leeuwenhoek could touch the world he had found. He could discover the life in water and then drink the water, the life in vinegar and then use the vinegar, the species on his own body and then go about his life.

Because it is hard to match Leeuwenhoek’s descriptions of the life around him to the modern names of species, we can’t tally just how many life-forms he might have seen, but it was certainly in the thousands. It is tempting to draw a straight line from Leeuwenhoek to the modern study of the life in homes, but this would be wrong. Upon Leeuwenhoek’s death, the study of the life in homes for its own sake was largely abandoned. Though Leeuwenhoek inspired the masses, he had no true colleagues in Delft after the death of de Graaf.11 His daughter may have worked with him during his later years, but she did not follow up on his observations after he died. While she was alive she kept his specimens and microscopes, but they went unused. After she died, as Leeuwenhoek himself had specified in his will, they were auctioned off. Most of his microscopes disappeared. The gardens where he made observations were subsumed by the growing edges of Delft. His childhood home, where his inspiration must have first flourished, fell into disrepair and was torn down in the nineteenth century; in its place now stands a playground for a school. The house in which he made so many discoveries was torn down too.12 A plaque was mounted to note the place where his house stood, but it was set in the wrong place. Another plaque was placed to remedy the error of the first; it, too, is not quite in the right location (one or two houses off depending on how one counts).

Eventually, other scientists would begin to study the life on human bodies and in homes anew. But by the time this happened, more than a hundred years had passed and it had been discovered that some microbial species could cause disease. These species were called pathogens. The idea that pathogens cause disease is the germ theory, credited to Louis Pasteur (though by the time Pasteur demonstrated that microscopic species could cause human disease it was already established that microscopic species could cause diseases in crop plants). With the advent of germ theory, pathogens became the focus of studies of microbial life indoors. Leeuwenhoek seems to have had an inkling that microscopic species could cause problems (he’d shown that some microbes could turn good wine into bad vinegar). He just imagined that most of the life he was seeing was harmless. In this, Leeuwenhoek was right. Of all the bacterial species in the world, for instance, fewer than fifty regularly cause disease. Just fifty. All the rest of the species are either benign or beneficial to humans, as are nearly all protists and even viruses (viruses wouldn’t be discovered until 1898, though they too were discovered in Delft). Once pathogens were known to be part of the invisible world, war was declared upon all invisible life indoors. The closer that life was to us, the more exhaustive the war. The study of peppercorns, gutter water, and the whimsical, whirling creatures found everywhere in the average home was abandoned. Time would make this abandonment ever more complete.

By 1970, nearly the only studies being done in homes focused on pathogens and pests and how to control them. The microbiologists who studied homes studied how to kill pathogens. Nor was it just the microbiologists. The entomologists who studied homes studied how to kill insects. The plant biologists who studied homes studied how to get rid of pollen. The food scientists who studied pepper considered whether it might be a source of food-borne illness. We forgot about the potential of the life around us to inspire wonder and left no room for the realization that the species around us might not only plague us but also help us. We became focused on only part of the story. This was a big mistake, one we have only very recently begun to remedy. The first big steps back toward a more holistic view of the life around us were taken at hot springs—in Yellowstone National Park and in Iceland—places that seem to have nothing to do with homes at all.



Let both curiosity and horror—the latter of which terrorizes us but also holds us rapt, unable to look away—be a motivator for discovery. Embrace the weird, the tiny, the things we’d like to ignore.

—BROOKE BOREL, Infested: How the Bed Bug Infiltrated Our Bedrooms and Took Over the World

IN THE SPRING of 2017, I was in Iceland filming a documentary about microbes.1 As part of the filming, we stood, again and again, beside bubbling, hot, sulfurous geysers where I was meant to point at the geysers and talk on camera about the origins of life. At one point, I was even abandoned at such a geyser, only to wait for the truck to come back to get me.2 Film crews can be unforgiving. While stranded, I had a moment to myself to contemplate the geysers. It was a cold day, and although they smelled sulfurous, I stayed near them. They kept me warm. The water in the geysers was boiling up from fissures in the Earth, warmed by the volcanism beneath the Earth’s crust. In some places, it is easy to forget that the Earth is tectonic, just as one can become numb to the night sky. Not in Iceland. The western and eastern halves of the island are tearing apart and the consequences of this great rip of stone and dirt are hard to miss. Sometimes volcanoes erupt so violently that they darken the sky. And every single day geysers, like those I stood beside, bubble up out of the ground. As they do, they sustain life, life that has far more to do with what is happening in your home right now than you’d ever imagine.

That species survive and thrive in the warmth of geysers was not discovered until the 1960s. Thomas Brock, then at Indiana University, worked in Yellowstone and then also in Iceland, not far from where I stood. Brock was fascinated by the colorful patterns around the geysers. A smeared palette of yellow, red, and even pink gave way to greens and purples. Brock thought these patterns to be the work of single-celled organisms.3 They were. The species present included bacteria but also archaea. The archaea are an entirely separate domain of life, as ancient and unique as the bacteria themselves.4 What was more, Brock discovered that many of the species in the geysers were “chemotrophs,” species able to turn the chemical energy of the geysers into biological energy; they made life from nonlife without the aid of the sun.5 These microbes were of the sort likely to have existed long before photosynthesis ever evolved, their communities akin to some of the first communities. They evoked Earth’s most ancient biochemistry. I could see them growing in a crusty mat around the geysers keeping me warm.

But these were not the only organisms in the geysers. Cyanobacteria were living in the hot water and photosynthesizing. In addition, Brock found bacteria that lived off of the organic matter swirling around in the bubbling water, be it the cells of other bacteria or a dead fly. Superficially, these scavengers were not very interesting. Unlike the chemotrophic bacteria Brock was studying, they couldn’t turn chemical energy into life and instead had to find and consume living and dead bits of other species. However, after some study Brock decided that they belonged to a new species and even a whole new genus. He called the genus Thermus for obvious reasons and the species aquaticus to reflect its habitat. For mammals or birds, finding a new species is a newsworthy event and finding a new genus, an even bigger deal.6 But not for bacteria. It isn’t hard to find new kinds of bacteria, and in terms of the features that microbiologists focus on first, this new species, Thermus aquaticus, didn’t appear terribly interesting: it didn’t form spores. Its cells were yellow rods. It was gram-negative. All true, all mundane. But there was something else.

Brock saw Thermus aquaticus in the lab only when he kept the growing medium (his cultures) at temperatures above 70 degrees Celsius (122 degrees Fahrenheit). It preferred even hotter temperatures and could still live at temperatures as high as 80 degrees Celsius (176 degrees Fahrenheit). The boiling point of water, for context, is 100 degrees Celsius, lower at higher elevations. Brock had grown what were among the most heat-tolerant bacteria on Earth.7 As he would later note, finding this life-form wasn’t hard. It was just that no one else had tried to grow microbes at temperatures so high. Laboratories had cultured samples from hot springs in 55 degrees Celsius culture conditions, too cold for Thermus aquaticus to grow well. Subsequent research has revealed an entire world of bacteria and archaea that can be grown only under very hot conditions. To such microbes, the temperatures at which we live out our ordinary lives are so cold as to be unlivable.

Why bring the story of Thermus aquaticus up in a book on houses? Because the temperatures and conditions found in geyseres and other hot springs, as unusual as they might seem, are very similar to those found around us in our daily lives. A student in Brock’s lab thought it possible that Thermus aquaticus or other similar bacteria were even living, unnoticed, alongside us. To test the idea, the student and Brock probed the coffeemaker in Brock’s lab, a machine that was plenty hot enough to favor Thermus. Given how much the machine helped fuel their work, it would have been an apt place to find the species. It wasn’t there.

Brock found himself wondering about other places around him that contained hot liquids, such as the human body. Human bodies are not nearly as warm as hot springs, but Brock thought perhaps the bacteria might be present anyway, holding out for moments of fever. Who knew? It was easy enough to check. So Brock “produced” a sample of human spit (in an email, he declined to note whether it was his own, which in my experience studying the behavior of scientists means it was). He tried to grow Thermus aquaticus from the spit. Nope, no Thermus aquaticus. He checked human teeth and gums (much as Leeuwenhoek might have). None there either, nor any other heat-loving bacteria. Neither were there any in the lake from which he took a sample, nor in the nearby reservoir. He also checked the cactus in the greenhouse in his building, Jordan Hall. Nothing. Perhaps it really was a bacterial species found only in hot springs.

Just to be sure, Brock checked one more location: the hot water tap in his lab in Jordan Hall. Brock’s lab was two hundred miles from the nearest hot spring. Yet, the lab’s tap water contained what looked to be Thermus aquaticus. This was fantastic. Brock wondered whether the hot water heaters provided the habitat for the microbe—the water in the tap was warm, but not like in a hot spring. The hot water heater itself should be nearly perfect. Maybe the bacteria lived in the hot water heater and every so often, inadvertently, rode downstream to the tap.

Eventually another pair of researchers, Robert Ramaley and Jane Hixson, both of whom also worked at Indiana University, did additional sampling of thermophilic bacteria around Jordan Hall. When they did, they too found a kind of thermally tolerant bacteria. It was similar to the Thermus aquaticus noted by Brock. But it wasn’t identical, so they called it Thermus X-1 for the time being.8 Unlike Thermus aquaticus, it wasn’t yellow. It was clear. Also, it grew faster than did Thermus aquaticus. Ramaley speculated that perhaps it was a new strain of Thermus aquaticus. Maybe the yellow pigment of Thermus aquaticus


  • "Utterly fascinating... a spirited romp through the vast diversity that inhabits our daily lives and how we've changed our ecosystems, often for the worse."—Washington Post
  • "In his fascinating new book...Mr. Dunn brings a scientist's sensibility to our domestic jungle by exploring the paradox of the modern home.... Mr. Dunn also gracefully explains, without getting bogged down in details, the technology that has allowed scientists during the past decade or so to sequence the DNA of millions of previously unknown microbes, making his book an excellent layperson's guide to cutting-edge research."—Wall Street Journal
  • "Chatty, informative... it's hard not to be occasionally charmed by [Dunn's] prose, as when he catalogs the arthropods with whom we share our homes... And it's hard not to share, at least a little, his awe at their diversity, even in a single household."—New York Times Book Review
  • "[A] fascinating and illuminating book... Dunn and his colleagues have used the concepts and techniques of community ecology to tease apart the functioning of a mostly ignored ecosystem: the human home. Their research enriches our understanding of ecosystem function, and--more grippingly--gives us insight into how our interactions with living things in the domestic habitat affect our health and well-being."—Nature
  • "Never Home Alone is a thumping good book that raises alarm and offers reassurance in roughly equal measure. And it is funny... What makes [it] so compelling is a sense of wonder and delight that encompasses all sorts of creatures and all sorts of science."—Los Angeles Review of Books
  • "Intriguing... Seen through Dunn's curious eyes, a house becomes not just a set of rooms, but a series of habitats to be explored. His writing and research lend a new appreciation of what many of us consider pests."—Science News
  • "If you're an insectophobe looking for a thrill, you'll love Rob Dunn's Never Home Alone, which details the thousands of species of insects and microbes that live in and around your home."—Bustle
  • "If you could somehow infuse the curiosity of a 6-year-old with Ph.D.-level intelligence, imagine what wondrous things you could learn. Or why not make it easier on yourself, and just read Never Home Alone. Yes, that delightful, open-minded gee-whiz is exactly what makes this book so enjoyable. Surprisingly, it's doubly so for a germophobe, an arachnophobe, or anyone who can't stand the idea of intruders. Dunn has a way of brushing fears aside so he can tell you about something that's too cool to miss, or a fact that makes you say, 'Wow!'... Science-minded readers will love this book. It's filled with things you'll want to know for the health of it. Really, for anyone who's alive, Never Home Alone is a book to share with a few million of your newest best friends."—Terri Schlichenmeyer, The Bookworm Sez columnist
  • "If you enjoyed I Contain Multitudes, this book should be next on your reading list. Just like Ed Yong shows readers the fascinating microorganisms all around us, Dunn opens our eyes to the minute creatures that live within the confinement of our own homes... a fascinating and entertaining read."—Read More Science
  • Finalist, 2020 Smart Book of the Year award—Jagiellonian University
  • "Wonderful."—TreeHugger
  • "Crammed full of eensy-weensy tales of wonder from the insect world.... On virtually every page, readers learn about these marvels and their potential applications so the benefit of humans, all of it written with the bounce and insight of a true believer...[a] hugely important book."—Open Letters Review
  • "A robust, scientific defence for both microbial life and for larger creatures too often exterminated simply because they've invaded our space. While data from copious end notes support staid scientific facts from strictly controlled lab tests, an engaging writing style enlivens narratives such as those about microbes in shower heads and beetles on windowsills, transforming Dunn's latest work into a profound understanding of how all living things help in constructing and maintaining our planet's complex web of life."—Winnipeg Free Press
  • "A good book about niche science, which deserves to be widely read."—Sunday Times (UK)
  • "Over a number of years, Rob Dunn, a U.S. biologist and ecologist and his team, surveyed the species to be found in 1,000 houses from around the world. The results, revealed in this remarkable, jaw-dropping, occasionally unappetising book, are astonishing."—Daily Mail (UK)
  • "A lively compendium of hard science, anecdote, history, and personal memoir.... Something of a scientific raconteur, Dunn tells his story of the macro and micro biome of our homes in a colloquial...stye that makes the heavy science go down easy."—Shelf Awareness
  • "[An] intriguing and captivating scientific detective story...Dunn eloquently observes that many species we find in our homes have value to us."—BookPage
  • "Scintillating... In a time of clear-eyed assessment of the environment, Dunn is a voice of reason who should be heartily welcomed."—Booklist, starred review
  • "Of course we must chlorinate our water, wash our hands, get vaccinated, and so on, Dunn argues persuasively and entertainingly. But we also need to relax and cultivate biodiversity for the good of all life on Earth."—Kirkus Reviews
  • "An entertaining tour of the biodiversity found in one of the fastest-growing biomes: indoors... This book will be enjoyed by biologists but also general readers with an appreciation for nature."—Library Journal
  • "Delightfully entertaining and scientifically enlightening... [Dunn] makes a compelling case for the value of biodiversity, while also conveying the excitement of scientific investigation, demonstrating that important discoveries can be made very close to home."—Publishers Weekly
  • "Easy to read and accessible... Recommended."—CHOICE
  • "Never Home Alone is a superb guide to your own house--a place that is home to hundreds of thousands of species--a far richer habitat than even the largest backyard. This riveting and surprising book is one of those rare volumes that will make you gasp out loud on almost every page, and phone your friends to report stunning fact after stunning fact. Thank you, Rob Dunn: I love our house even more now I understand it shelters multitudes of fascinating (and mostly benevolent) living creatures."—Sy Montgomery, author of The Soul of an Octopus
  • "If you're looking for a guide to the teeming, tiny, tenacious creatures that share our bodies, our homes--and may one day well inherit our planet--you could not do better than this fascinating book by Rob Dunn."—Deborah Blum, author of The Poisoner's Handbook
  • "Rob Dunn is a brilliant explorer of the strange, mostly uncharted biology of our homes and bodies. This must-read book is full of astonishing stories, skillfully told."—David George Haskell, author of The Songs of Trees and The Forest Unseen
  • "If you truly want to know yourself and be amazed, get to know your ecology. This charming book shows how important and fun it is to discover the astonishing world of marvelous and unseen creatures around us. You'll never take a shower again in the same way!"—Daniel E. Lieberman, author of The Story of the Human Body
  • "In Never Home Alone, Rob Dunn reveals the unseen wilderness that surrounds us every day. This book will change the way you think about everything from dust to spiders to showerheads--a fascinating and highly recommended read!"—Thor Hanson, author of Buzz, Feathers, and The Triumph of Seeds
  • "A Brooklyn couple visiting the West told me, 'We don't do nature.' Today, I'm sending them a copy of Rob Dunn's Never Home Alone, with this note: 'Nature made you, so roll in the dirt, open the windows, get a dog. Change your showerhead, but don't kill your spiders. And read this terrific book at once.'"—Dan Flores, author of Coyote America

On Sale
Nov 6, 2018
Page Count
336 pages
Basic Books

Rob Dunn

About the Author

Rob Dunn is Reynolds Professor in the Department of Applied Ecology at North Carolina State University and in the Center for Evolutionary Hologenomics at the University of Copenhagen. He is also the author of seven books. He lives in Raleigh, North Carolina.

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