When Steve Duneau took home a puppy—a skinny, flea-bitten foundling from the side of a California road—he had no idea how his whole life would change. Lou, as he named his dog, turned out to be endowed with inexhaustible energy, devotion and a love of adventure. Lou accomplished many feats, he stood up to armed robbers and single-handedly apprehended a rapist. But, most importantly, thanks to him, Steve became seriously interested in studying animal behavior. Together with Lou, they rehabilitated aggressive dogs and saved hundreds of animals that would otherwise have been euthanized. Lou knew more than a hundred words, and there was no doubt that he was very smart. But also - and this is the most important thing - he was funny, unique, heroic and, for sixteen years, he was Steve's best friend.