An engaging introduction to the systems of the human body and the components of the environment that affect health. In the first half of the book the reader learns about the various systems that make up the body-digestive, respiratory, circulatory, and excretory, as well as the muscles, bones, and joints that allow it to move, the sense organs that enable it to interact with its environment, and the brain and nervous system that control it all. Over two dozen labeled illustrations are included that students can render in their own notebooks as part of the learning process. For further study the author recommends examination of animal organs, such as eye, heart, kidney, and brain that can be obtained from the butcher or purchased in a dissecting kit. The second half of the book deals with establishing habits conducive to healthy living, through choices in clothing, food, and home environment. Given that the choices were more limited a century ago when this book was written, the second half of this book is less useful than the first. The four color illustrations in the original edition are rendered in black and white in this edition. Visit the Yesterday's Classics website for a downloadable pdf of the four color illustrations.