The heart, the main organ of the human body, is the subject of this informative text. In a straightforward fashion, Dr. Zim outlines its capacity, structure, function, evolution, relationship to other organs, and the techniques with which science approaches it. Illustrated diagramatically by Gustav Schrotter, Your Heart and How It Works, like Herbert Zim's previous books, maintains a standard of clarity and factual generosity which recommends it as a valuable supplement to classroom study.