How did wolves evolve into dogs? When did this happen, and what role did humans play? Oxford geneticist Bryan Sykes explores the canine genetic journey that began many thousands of years ago—most likely when a human adopted a wolf cub—and finds that only a handful of genes are responsible for the huge range of shapes, sizes, and colors in modern dogs. Illustrated with 20 photographs, Sykes's thought-provoking homage to man's best friend delves into how our own evolution was in turn enhanced by this singular ally, and seeks to answer the most fundamental question of all, "Why do we love our dogs so much?"