Everyone interested in the modern problems of eugenics and the care of defectives will find much of value in this book. The author says: “An attempt has been made to summarize for the intelligent but uninitiated reader some of the more recent phases of the questions of heredity which are at present agitating the biological world.” The book is an excellent statement of the present most generally accepted theory of heredity, with only as much reference to other theories as will enable the reader to see how modern theories have grown out of the old ones. Much of the book is extremely interesting to anyone with the least beginning of a scientific mind. The incidents with regard to the various experiments by biologists are illuminating. The author is fair and guarded in his statements on questions which are in dispute. Although there can be no doubt as to his own beliefs in such matters, for example, as the inheritance of acquired characters, yet he gives both sides of the question fairly. Some of the instances of experiments read like a romance. The story of Lamarck’s Evening Primrose as studied by De Vries is fascinating. Of course, to the socially minded person, the most interesting part of the book is that which deals with its application to man, and the chapter on human conservation which takes up such topics as how mankind may be improved, control of immigration, discriminating marriage laws, educated sentiment, segregation of defectives, etc., is compelling and well worth study. The text is illustrated by a large number of diagrams some of which, although simple to the student of biology, will require considerable study by the ordinary reader. On the whole, the book is a valuable contribution to our literature on heredity and will be of great service to those who, while unable to study eugenics exhaustively, still feel that they must know the general theories on the subject. ALEXANDER JOHNSON. MARRIAGE AND THE SEX PROBLEM By DR. F. W. FOERSTER. Frederick A. Stokes Co. 225 pp. Price $1.35: by mail of THE SURVEY $1.44. This is a translation of a work entitled _Sexualethik und Sexualpadagogik_ by Dr. F. W. Foerster of Zürich, Switzerland. The translator supplies a brief statement of Foerster’s personal development and his final adoption of a positive ethical and religious philosophy akin to the new idealism of Prof. Rudolph Eucken. The book devotes considerable space to the theories of Ellen Key, Freud and Forel. On its positive side it advocates undeviating adherence to the traditional point of view in matters of sex and marriage. A somewhat pedantic touch results from the translator’s use of “ethic” in preference to the more familiar “ethics” as an equivalent for the German _Ethik_. KATHARINE ANTHONY. BEDROCK