I Contain Multitudes has a terrific story to tell ... covers a huge amount of microscopic territory in clear, strong, often epigrammatic prose. Yong has advanced degrees in biology, and he is remarkably well informed ... He is infectiously enthusiastic about microbes, and he describes them with verve.
...[a] beautifully written account ... Yong — who like Carl Zimmer belongs to the highest tier of science journalists at work today — weaves revelatory anecdotes and cutting-edge reporting into an elegant, illuminating page-turner that deserves a broad readership ... But I Contain Multitudes is hardly pure science. Yong paints a lavish mural teeming with vivid characters.
...[a] marvellous, thrilling and richly annotated book ... And it is a page-turner in a very old-fashioned sense. All life is here, and death too, and sex and violence, including deviations of which you had never dreamed ... We have an inner life, in every sense, and are the richer for it: richer still for this witty and compelling book.