This volume, edited by Max Rinkel and H. C. B. Denber, consists of fifteen chapters by different authors—a series of separate, unconnected communications, but united by a common theme and by the fact that they were presented at an international Congress in Zurich in 1957. Several of the chapters have already been published elsewhere, and the inquiry by a given author has subsequently been pushed further. Despite its belated appearance, this is an important volume, since it includes under one cover the views of most of those working in western countries who are interested in chemical concepts of the psychoses. The main theme that runs through the book, and is exemplified in different ways by different authors, is that psychotic patients as a group, notably schizophrenic patients, exhibit manifestations of impaired cerebral function, as a result of circulating noxious humoral agents that originate outside the brain and interfere with its