I, Mammal is Liam Drew’s thorough, detailed, and at times chatty exploration of the rise and evolution of mammals, one precipitated by the birth of his daughter, his wife’s nursing of her, and an “excruciating whack of pain in my crotch” from a soccer ball. Covering roughly 300 million years, from scientists’ best estimate of when mammals and reptiles diverged, the book is organized not sequentially but by traits, including reproduction, warm-bloodedness, brain complexity, sexuality, and of course, scrotums and lactation.

After a general background offering up basic numbers and definitions and some discussion of classification, he moves back and forth in time in each section, and though this does perhaps dilute a big picture sense of chronology, it does create a layering effect so that the reader is able to create a greater sense of context as the book progresses. And as he adds more traits to the mix, he’s always careful to emphasize that what makes a mammal a mammal is not a list of individual traits but the ways in which they work as a whole, and that therefore it is impossible to tease out their evolution in isolation.

While aiming at a lay audience, it’s a pretty exhaustive and at times dense book (reflected by the unusual number of notes and highlights on my Kindle), with lot of detailed explanations and descriptions requiring close attention and maybe even some brief rereading of passages. I admit to bogging down a bit now then, say in some paragraphs relating close anatomical detail, but mostly it’s all pretty fascinating material.

Drew is enthusiastic throughout, but is always careful to identify when theories come with a lot of speculation or controversy, and when possible, he offers up both sides (or more if needed) of a controversial topic fairly and evenly. The language and tone are playful at times, which mostly makes for an engaging, entertaining read, though at times it tipped over into a distraction for me. One’s mileage will vary I suspect. But that’s a minor complain in a thoroughly informative work of non-fiction. Recommended

Good source of information with very good references. This book can be used in high schools or university libraries for general information about mammal evolution. The book helps to understand the links between the mammals. Very interesting and educational.