Animals have always occupied a privileged place beside man and with him form a couple, a duality. In the first part the authors study the psychology of the adopted animal. Then they look at greater length into the personality of his owner, with particular insistence on the reasons for acquiring it, on the choice of animal (dog, cat, horses), on the part it plays in the life of its master, and on the latter's reaction at his companion's death. They also tackle the problem of man's abnormal behaviour in relation to animals, especially bestiality.