What controls our growth and emotional response to fear and sadness? The answer is hormones, chemicals secreted by specialized glands that travel through the blood and act on target cells and tell them what to do. Major glands described are the pea-sized pituitary found in the brain that, with the hypothalamus, controls other glands; the pineal gland that helps us sleep; the thyroid gland that controls metabolism; parathyroids that control calcium; and adrenal glands affecting the heart and the release of sugar into the blood. Although the pancreas is mentioned as making insulin, technically the islets of Langerhans are the endocrine glands within the pancreas that produce the hormone. The reproductive hormones are not included in the text. Diabetes is highlighted as an endocrine problem, and the importance of eating the right foods and getting enough exercise is discussed, not only to keep the endocrine system healthy, but the body as a whole. Each topic is explained in easy-to-read print with a related photo or illustration on the opposite page. Significant words are highlighted and explained in a glossary. A few references are given for further study. This book is one of "Bridgestone Books Human Body Systems" series and an excellent introduction to body functions.