This work presents the basic concepts regarding the behaviour of domestic dogs and cats, and explains the disorders most commonly encountered in everyday clinical practice. The book describes the main signs of behavioural disorders, their diagnosis, prognosis, and treatment, all illustrated with images taken from actual cases. It is a quick, accurate reference guide that should prove particularly useful for veterinary practitioners, as it will help them advise new pet owners and enable them to carry out appropriate primary interventions to resolve their patients’ behavioural disorders early on in their development.