This extensive monograph on an old and perennially interesting disorder, for many years resident in the borderland of neurosis, consists of seven sections, preceded by a Foreword. The Historical Review traces thought about it from Woodward and Da Costa to the present. The second section (Clinical Syndrome), aside from the usual considerations implied by the title, emphasizes the frequency of low physical efficiency and the importance of evidence of dysfunction of the autonomic nervous system (without clearcut preponderance.) The presence of symptoms of increased tension in the physiological as well as the psychological activities of the central nervous system is also noted. The third section (Experimental Production of Lesions) surveys the experimental field briefly, with special reference to previously published work of two of the authors, concerning induced changes in the rectosigmoid mucosa of normal medical students. The section on