Beton Precontraint, by Y. Guyon. Preface by E. Freyssinet. (Paris : Eyrolles, 1951.) Pp. 728, 1O in. x 7 in., 503 Figs. 4,500 Fr. As the author points out in the preface, prestressing is a general principle which may be employed by different means in a great variety of cases. To write a complete treatise on the subject seems to be an impossible task. The purpose of the author is to develop general principles by analysing a few applications in detail and to describe the methods of execution which may be adopted for other applications. The present book, comprising 700 pages, is the first volume of a comprehensive work on the subject.