This is an extremely technical work concerning methods of handling statistical data on heredity. There are numerous mathematical equations, which a clinician will have difficulty grasping. The conclusions regarding the rôle of heredity in the production of psychoses are dealt with elsewhere. The book represents the technical attitude of the workers in the Munich institute toward the general problem. Once the material is obtained, it is probably satisfactorily handled mathematically. The clinican, however, wonders about the accuracy of diagnosis, the type of clinical records and the longitudinal studies of individual patients as they may affect the stuff with which the statistician deals.