This series of lectures on heat production and heat loss, with a discussion of physiologic mechanisms involved, constitutes a readable account of the important studies by Du Bois and his collaborators. It is the result of many years of work, which have served to mature the point of view and increase the value of the presentation. One of its main virtues lies in the synthesis of anatomic, biochemical, physiologic and clinical material in a critical manner. It demonstrates better than words the value of the scientific approach to the problems of practical medicine. The book is to be recommended to all students of calorimetry in the laboratory and the clinic.