This little book, dedicated "To the Man of To-Morrow," is an effort to impart instruction to boys on sexual hygiene. It is interestingly written in the form of talks to a boy by his uncle. Beginning with a description of plant life and the method of plant reproduction, the reader is gradually led through the lower forms of animal life, with which he is naturally familiar, to the chapter on "The Mechanism of Our Bodies," the needed information being imparted in a natural and unsensational manner. Chapters containing needed warnings to boys on the dangers of listening to the advice of advertising fakers and a chapter on "Sowing Wild Oats," containing advice to the boy about to leave home, are particularly good. The tone of the book is excellent and it can be safely recommended to parents and others who wish to instruct children in this important subject.