Ed Yong is a London-based science writer for The Atlantic and is part of National Geographic’s blogging network. I had trouble believing that I Contain Multitudes: The Microbes within Us and a Grander View of Life is his first book; it’s so fluent and engaging that it immediately draws you into the microbial world and keeps you marveling at its strange yet fascinating workings. Yong writes like a journalist rather than a scientist, and that’s a good thing: with an eye to the average reader, he uses a variety of examples and metaphors, intersperses personal anecdotes of visiting researchers at their labs or in the field, and is careful to recap important facts in a lucid way.
The book opens with a visit to San Diego Zoo (see the exclusive extract following my review), where we meet Baba the pangolin. But “Baba is not just a pangolin. He is also a teeming mass of microbes,” Yong explains. “Some of them live inside him, mostly in his gut. Others live on the surface of his face, belly, paws, claws, and scales.” Believe it or not, but we are roughly half and half human cells and microbial cells, making each of us – like all creatures – more of an ecosystem (another term is “holobiont”) than a single entity.
Microbes vary between species but also within species, so each individual’s microbiome in some ways reflects a unique mixture of genes and experiences. This is why people’s underarms smell subtly different, and how hyenas use their scent glands to convey messages. The microbiome may well be tailored to different creatures’ functions, so researchers at San Diego Zoo are testing swabs from their animals to see if there could be discernible signatures for burrowing or flying activities, or for disease. I was struck by the breadth of species considered here: not just mammals, but also invertebrates like beetles, cicadas, and squid – my entomologist husband would surely be proud. The “Us” in the subtitle is thus used very inclusively to speak of the way that microbes live in symbiosis with all living things.
If I were to boil down Yong’s book to one message, it’s that microbes are not simply “bad” or “good” but have different roles depending on the context and the host. You can hardly dismiss all bacteria as germs that must be eradicated when there are thousands of benign species in your gut (versus fewer than 100 kinds that cause infectious diseases). If it weren’t for the microbes passed on to us at birth, we wouldn’t be able to digest the complex sugars in our mothers’ milk. Other creatures rely on bacteria to help them develop to adulthood, like the tube worms that thrive on Navy ship hulls at Pearl Harbor.
Yet Yong feels too little attention is given to beneficial microbes, and in many cases we continue the campaign to rid ourselves of them through overuse of antibiotics and taking cleanliness to unhelpful extremes. “We have been tilting at microbes for too long, and created a world that’s hostile to the ones we need,” he asserts.
The book is full of lines like that one that combine a nice turn of phrase and a clever literary allusion. In the title alone, after all, you have references to Walt Whitman (“I contain multitudes” is from his “Song of Myself”) and Charles Darwin (“there is grandeur in this view of life” is part of the closing sentence in his On the Origin of Species). Yong also sets up helpful analogies, comparing the immune system to a thermostat and antibiotics to “shock-and-awe weapons … like nuking a city to deal with a rat.”
History and future are also brought together very effectively, with the narrative looking backwards to Leeuwenhoek’s early microscope work and Pasteur and Koch’s germ theory, but also forwards to the prospects that current research into microbes might enable: eliminating elephantiasis, protecting frogs from deadly fungi via probiotics in the soil, fecal microbiota transplants to cure C. diff infections, and so on.
The possibilities seem endless, and this is a book that will keep you shaking your head in amazement. I’d liken Yong’s style to David Quammen’s or Rebecca Skloot’s. His clear and intriguing science writing succeeds in inspiring wonder at the natural world and at the bodies that carry us through it.
With thanks to Joe Pickering at The Bodley Head for the review copy.
My rating: 
An exclusive extract from “PROLOGUE: A TRIP TO THE ZOO”
I Contain Multitudes by Ed Yong
(The Bodley Head)
All of us have an abundant microscopic menagerie, collectively known as the microbiota or microbiome.1 They live on our surface, inside our bodies, and sometimes inside our very cells. The vast majority of them are bacteria, but there are also other tiny organisms including fungi (such as yeasts) and archaea, a mysterious group that we will meet again later. There are viruses too, in unfathomable numbers – a virome that infects all the other microbes and occasionally the host’s cells. We can’t see any of these minuscule specks. But if our own cells were to mysteriously disappear, they would perhaps be detectable as a ghostly microbial shimmer, outlining a now-vanished animal core.2
In some cases, the missing cells would barely be noticeable. Sponges are among the simplest of animals, with static bodies never more than a few cells thick, and they are also home to a thriving microbiome.3 Sometimes, if you look at a sponge under a microscope, you will barely be able to see the animal for the microbes that cover it. The even simpler placozoans are little more than oozing mats of cells; they look like amoebae but they are animals like us, and they also have microbial partners. Ants live in colonies that can number in their millions, but every single ant is a colony unto itself. A polar bear, trundling solo through the Arctic, with nothing but ice in all directions, is completely surrounded. Bar-headed geese carry microbes over the Himalayas, while elephant seals take them into the deepest oceans. When Neil Armstrong and Buzz Aldrin set foot on the Moon, they were also taking giant steps for microbe-kind.
When Orson Welles said ‘We’re born alone, we live alone, we die alone’, he was mistaken. Even when we are alone, we are never alone. We exist in symbiosis – a wonderful term that refers to different organisms living together. Some animals are colonised by microbes while they are still unfertilised eggs; others pick up their first partners at the moment of birth. We then proceed through our lives in their presence. When we eat, so do they. When we travel, they come along. When we die, they consume us. Every one of us is a zoo in our own right’– a colony enclosed within a single body. A multi-species collective. An entire world.
Footnotes
- In this book, I use the terms ‘microbiota’ and ‘microbiome’ interchangeably. Some scientists will argue that microbiota means the organisms themselves, while microbiome refers to their collective genes. But one of the very first uses of microbiome, back in 1988, used the term to talk about a group of microbes living in a given place. That definition persists today – it emphasises the ‘biome’ bit, which refers to a community, rather than the ‘ome’ best, which refers to the world of genomes.
- This imagery was first used by the ecologist Clair Folsome (Folsome, 1985).
- Sponges: Thacker and Freeman, 2012; placozoans: personal communication from Nicole Dubilier and Margaret McFall-Ngai.
My gut feeling: This book is a fine example of popular science writing, and has much to teach us about the everyday workings of our bodies. It’s one of my three favorites from the shortlist.
See also: Paul’s review at Nudge
Shortlist strategy: Tomorrow I’ll post a quick response to David France’s How to Survive a Plague, and on Sunday we will announce our shadow panel winner.
I was delighted to be asked to participate in the Wellcome Book Prize blog tour. See below for details of where other reviews and features have appeared or will be appearing soon.
And if you are within striking distance of London, please consider coming to one of the shortlist events being held this Saturday and Sunday.
Who knew Elizabeth Gilbert had it in her? I’ve read and loved all of her nonfiction (e.g. 
Lab Girl, Hope Jahren: An enthusiastic, wide-ranging memoir of being a woman in science. There’s even some moss! This was a really interesting one for me to be reading at the same time as the Gilbert novel. (See Naomi’s review at 
The Paper Garden, Molly Peacock