This book has been prepared for and is dedicated to the college student. In part I, on constructive hygiene, the contents are based on the "constructive hygiene of the single cell." The subjects discussed include heredity, nutrition, excretion, physical exercise, play and rest. These are discussed from a scientific point of view, in a logical and clear manner. Part II contains a discussion of what the author calls defensive hygiene. This is dealt with from two angles, one being "autonomic defensive hygiene" and the other "voluntaristic." The hazards concerned with heredity, heritage, food, play, accidents, chemical poisonings and micro-organisms are discussed. The author evidently regards the college student as an intelligent and thinking individual and does not try to dose him with predigested facts. Explanations of the various subjects discussed are given so far as knowledge permits. The book can be enthusiastically recommended to teachers of hygiene in colleges.