The field of biology has been wildly successful by taking what’s called a reductionist approach, i.e., you tackle a small problem in isolation in order to gain insight into larger questions. In his new book, Microcosm: E. coli and the New Science of Life, Science writer Carl Zimmer took that reductionist approach and applied it to a pretty big issue: life itself. For Zimmer, the system that serves as a model of all life, and of humanity’s often uncomfortable relationship to it, is the unprepossessing gut bacteria, Escherischia coli. Covering all of life is a big task, and Zimmer made the challenge that much harder on himself by choosing to target the book to a general audience. Still, he