This book deals with the intelligence of dogs and cats.

The emotional life of the dog is highly developed, more highly, indeed, than that of any other animal. His gregarious instincts, united with his high intelligence and constant companionship with man, give to this animal a psychological basis for the construction of emotional character, having a more massive as well as more complex consistency than that which is presented even in the case of the monkey, which, as we shall afterwards see, attains to a remarkably high level in this respect.

The cat is unquestionably a highly intelligent animal, though when contrasted with its great domestic rival, the dog, its intelligence, from being cast in quite a different mould, is very frequently underrated. Comparatively unsocial in temperament, wanderingly predaceous in habits, and lacking in the affectionate docility of the canine nature, this animal has never in any considerable degree been subject to those psychologically transforming influences whereby a prolonged and intimate association with man has, as we shall subsequently see, so profoundly modified the psychology of the dog.