In the preface of this book the authors state that they "have attempted to summarize the more important recent research concerning vitamin D and ultraviolet light, and in particular their influence upon the calcium and phosphorus of the body." Without doubt, this object has been attained. An idea of the scope of this work may perhaps be obtained by giving the titles of some of the chapters; for example, "The Calcium and Phosphorus of the Body"; "Tooth Development and the Antirachitic Vitamin"; "Ultraviolet Light"; "Distribution of Vitamin D"; "Irradiated Foods and Irradiated Ergosterol."
It is evident from the beginning that the authors have a first hand knowledge of and are fully acquainted with the literature of the subjects they treat. This is true not only of laboratory studies, but of the many clinical investigations that have been published during the past decade on this highly interesting subject. They have likewise