Some working dogs are able to use their skills to perform tasks they were bred for; there are still jobs today for herders, hunters and guard dogs. But as we multiply and transform the many breeds of dogs, honing their looks and their sizes, we also change our relationship with them, and theirs with us. How can we learn to cope with the hard-wired instincts of our pets, and what roles can they play in a world their ancestors would hardly recognize?