The James Jackson Putnam Professor of Neurology at Harvard has contributed a fine and discriminating essay on psychotherapy to the series of Harvard Health Talks. The little work fulfils completely its object, as set out on the title page; it deals with the mental elements in the treatment of disease. Dr. Taylor divides his subject into five periods: (1) the age of magic; (2) the age of Mesmer; (3) the early scientific method, Braid; (4) the clinical period, Charcot and Janet; (5) analytical school of Freud and Jung. He rightly claims that whilst many have benefited at all periods from this form of medical treatment, it is only recently that we have begun to study and establish the general principles of mental reaction. This is, in the opinion of the authors, the concrete addition which the Freudian school has made towards practical knowledge, and this alone constitutes rational psychotherapy.