The book Psychotherapy by Reciprocal Inhibition (1968) is widely acclaimed as the masterwork of Joseph Wolpe, a great pioneer in the development of behavioural therapy, and is considered one of the most influential books in the history of clinical psychology. In this article, a brief biography of Wolpe is followed by a critical review of the book that illustrates his major contributions to the evolution of cognitive–behavioural therapy (CBT) as the most empirically supported model of psychotherapy.