Wherever humans have gone in the New World, dogs have been their companions, from the time people crossed the Bering Land Bridge some twenty thousand years ago.

In this remarkable history of the interaction between humans and dogs, Mark Derr looks at the ways in which we have used canines-as sled dogs and sheepdogs, hounds and Seeing Eye dogs, guard dogs, show dogs, and bomb-sniffing dogs-as he tracks changes in American culture and society. From the Spanish conquest of the Americas to the English colonial period, from the age of revolution to slavery, from World War II to the Vietnam War, Derr weaves a remarkable tapestry of heroism, betrayal, tragedy, kindness, abuse, and unique companionship. The result is an enlightening perspective on American history through the eyes of humanity's best friend.