I Contain Multitudes Book

I Contain Multitudes Book

The Microbes Within Us And a Grander View of Life

By Ed Yong

Available for purchase from Amazon

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Quick Take

The I Contain Multitudes book is at once a history book and a science book, charting the course of life on earth from the very beginning, and exploring the science behind our evolving understanding of the microbial world in which we live, delving deep into the manner in which these microbes shape that world, both around, and in us.

It is decidedly not a how-to book regarding your personal health, so readers looking for recipes or recommendations for medical conditions should look elsewhere (The Microbiome Solution would be a better bet for that)

However, it does provide a solid and useful foundation for your understanding of such issues and an appreciation for the importance and resourcefulness of these trillions of microorganisms with whom you share your body, and your world.

Rating: 4.5 out of 5 Stars

Four and one half stars

Well written, well documented, and well-rounded, I Contain Multitudes will provide you a top-level understanding of the critical role microorganisms play in all aspects of life on earth and will very likely change the way you look at the world and possibly even your place in it.

That said, I believe it could have used another cut at editing. This is a book, after all, that begins at the very dawn of life on earth and explains how bacteria themselves came to be.

There is, for example, an entire chapter on coral reefs, and while not wholly irrelevant, didn’t really add anything essential to a narrative that was already pretty lengthy (267 pages of small-type text in the paperback (357 including notes and bibliography), and nearly 10 hours for the audiobook) and seemed more like an add-on because the writer happened to have some extra material lying around.

I also thought the title, while a clever play on a Walt Whitman quote, suggested a book more focused on the human microbiome. Instead, well over half the book focuses its attention elsewhere.

Those minor nits aside, I felt it was well worth my time, and my understanding of the microbiome, human and otherwise, is much the richer for it.

Hype Meter

Hype Meter: Safe

Written by Ed Yong, a science writer, who, while having an obvious passion for the subject, had no obvious personal agenda other than to bring you along on his journey of discovery. Meticulously documented with end notes, and with no grandiose claims of miracle cures but rather cautions regarding the still-early state of our understanding of the human microbiome, this book is essentially free from hype.

Clever Turns of Phrase

“(Antibiotics) kill the bacteria we want as well as those we don’t, an approach that’s like nuking a city to deal with a rat.”

“If your microbiome has fewer species than a hunter-gatherer’s is it dysbiotic (dyfunctional)? The term is great at conveying the ecological nature of disease but it’s also become microbiology’s version of art or pornography. You know it when you see it.”


There is a flatworm that can regenerate severed body parts only because of the bacteria it harbors. The surprising consequence of this arrangement is that the bacteria-laden tail, if cut off, can regenerate a head, but the bacteria-free head, if cut off, can’t regenerate a tail.

After H. Pylori was determined to be the primary cause of ulcers and placed people at greater risk for stomach cancer, it was treated as a pure pathogen and has been the target of eradication efforts for decades. However, it has become clear that H. pylori also helps reduce acid reflux and the risk of esophageal cancer. And it doesn’t seem to matter which you choose, mortality rates are the same with or without H. pylori present.

Actionable Advice

While not a how-to book, there are some bits of actionable advice you can glean from this material. For example, the author notes that “saturated fats can nourish inflammatory microbes,” suggesting it is best to avoid such foods (I have started paying more attention to my intake of saturated fat having read this book).

The author also further supports the notion that when it comes to antibiotic use, we need to abandon the notion that there are no downsides, and instead carefully weigh the pros and cons.

However, the main benefit of this book for me was that it undeniably enriched my understanding of the overall microbial world, including the multitudes within us. I am more convinced than ever that we ignore our microbiome at our peril.

That doesn’t mean we should buy into every claim of a miracle cure, quite the opposite as the author explicitly points out. Instead, we can proceed with a combination of both caution and wonder at the power these vast communities of tiny but influential living things have on our lives.

Quick Note on The I Contain Multitudes Audiobook

There are some obvious and jarring edits you have to endure with the audiobook. They are not frequent, but occasionally the sound quality and tone changes in a way that makes it clear that the passage or phrase was recorded elsewhere at a different time and on different equipment. I was surprised this couldn’t have been cleaned up in post-production.

Otherwise, the narrator, Charlie Anson, is excellent. A classically trained theater actor who is also known for his work in Downtown Abbey among other productions, does a superb job of bringing the material to life. His pronunciation of certain words might sound unfamiliar to an American ear, but this in no way detracts from the reading, and in fact, adds a bit of novelty.

Before You Go…

Thanks so much for stopping by and spending some time with us. If you are interested in purchasing this book (available in most forms), you may do so here through Amazon (please see our Affiliate Disclosure for linking policies). Purchasing through this link doesn’t cost you anything additional, but doing so does help support the work we do here, and for that we are grateful.

If you have any questions, comments, or observations, please leave them in the comments below. And if you’ve read this book, please let us know what you got out of it, whether a surprise, a clever turn of phrase, or actionable advice!

Take care and we’ll see you next!