In this book, young readers curious about how the body works find a simple explanation of the circulatory system, beginning with the thump of the heartbeat, the flow of blood through the chambers of the heart, and explanations of the function of arteries, veins, and capillaries. The role of blood vessels in delivering needed oxygen to the body's cells and the removal of waste is accompanied by a dramatic and colorful image showing the network of blood vessels in the hand. The blood components of red cells, white cells, and platelets are shown greatly magnified with the red cells a vivid red demonstrating the hemoglobin they carry. The reader is reminded to eat and drink calcium to meet the needs for bone, heart, muscle, and nerve health. Brief sections on circulatory problems and keeping the heart healthy introduce the reader to a healthy lifestyle. Each topic is explained on one page 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 the "Bridgestone Books Human Body Systems" series and an excellent introduction to body function for early readers.