An informative and very readable survey of the body chemicals comes from the author of How Man Discovered His Body, Water for People etc. and adds to her record of good non-fiction for readers in their teens. Much of the text is on-the- scene reporting of the work of such men as Best and Banting, the discoverers of insulin, and these passages are well woven in to give the explanations of the hormones themselves more practical meaning. Discussing the normal body balance,- what a hormone is and does, some of its remarkable manifestations in the animal world, human growth and shape glands and the change from childhood to adulthood, the book is itself a well rounded and balanced entity. With its open and sensible talk on touchier subjects such as sexual development and certain physical abnormalities, as well as the clear explanations of the hormones and their related functions, this should prove a fine aid to high school studies.