Carl Zimmer’s Microcosm: E Coli and the New Science of Life (Pantheon Books) delivers what a science book should; it reveals the new and re-enchants the old. By looking at the process common to all life through the prism of an organism with no public persona to distract us—the bacterium Escherichia coli, uncomplaining workhorse of ten thousand laboratories, unobserved and mostly benign passenger in the guts of us all—he is able to draw out all sorts of implications form one of the 20th century’s great discoveries. At the cellular level, a vast amount of what drives and allows life is the same the world over: as the molecular biologist Jacques Monod remarked, “What is true for E coli is