A firsthand exploration of the fascinating world of "working dogs"--who seek out missing persons, sniff for explosives in war zones, and locate long-dead remains--through the experiences of a journalist and her canine companion, an incorrigible pup named Solo. Cat Warren is a tenured university professor and a journalist with what she acknowledges is an odd hobby: She and her dog have spent the last seven years searching for the dead. In What the Dog Knows, Warren recounts her adventure into the world of missing persons, and what she's learned about the capabilities of canines in the process. It all started as an effort to harness the wild energies of her German shepherd puppy, Solo, who had a fine nose but didn't play well with others. Before long, Warren and Solo were training with the police K9 unit in Durham, North Carolina, called out to sniff the parks, woodlands, and cul-de-sacs for bodies of the missing. Warren leads us onto trails of mystery that are sometimes solved, and often not. At investigator and handler trainings, "body farms," and crime scenes, she works and talks with forensic anthropologists, detectives, and dog handlers--learning why dogs are particularly well suited for this type of work, and how people are helping them get even better at the task. Along the way, she offers a fascinating exploration of canine intelligence and training, and she digs deep into scent research to unveil the amazing science behind a dog's ability to smell what humans can't even fathom. Combining the science-writing chops of Mary Roach with the visceral appeal of books like Inside of a Dog, Warren offers a unique perspective on special place that working dogs have in our society, and in our hearts and minds.