A life as scrutinized as Darwin's presents a challenge to a writer, requiring a well-conceived plan of approach. Quammen, a popular author on evolution-related topics, devises one that reaches an audience intrigued by Darwin but lacking the stamina for Janet Browne's authoritative two-volume biography. Writing in a flexible style that allows for asides about Darwin's reclusive personality and procrastinating habits, Quammen also assumes that his readers already know something about the voyage of the Beagle, and so omits it, choosing to raise the curtain on Darwin after the voyage, when he married and settled near London. Quammen tracks his correspondence, copious because Darwin recoiled from socializing yet sought continual exchange with fellow naturalists, and these letters contain quotations galore that have since become famous. Quammen sets the excerpts in a companionable narrative that collects Darwin's eccentricities, appealing sensitivity, and intellectual journey into formulating the foundations of evolutionary theory. Walking readers through the origin and the content of The Origin of Species, Quammen proves an informative, often wry guide to Darwin's life and continuing influence.