In 1090, Mark Derr wrote a controversial article for the Atlantic Monthly challenging the American Kennel Club to cease overbreeding dogs which, in his judgment, has "led to an epidemic of genetic disorders and the loss of temperamental soundness and working ability in most purebred dogs." In Dog's Best Friend, an expanded version of his contentious piece, Derr chronicles how man's relationship to dogs was formed and asserts that many of us are unknowingly cruel friends to our canine companions. Dog's Best Friend includes a history of how dogs were domesticated; an overview of dog types; descriptions of how dogs were, and still are, trained for and worked in a variety of jobs and sports; and how overbreeding for appearance can undermine the mental and physical health of dogs. Along the way Derr addresses a number of controversies, both political and scientific, and tells compelling stories about a great many - mostly large - dogs.