Isaac Asimov describes in detail the structure and functions of the human body, which he perceives as a particle of the biosphere. Fascinatingly talks about the skeletal frame, muscles, circulatory and digestive systems, as well as the heart, liver, lungs, kidneys - the organs that power and supply energy to a living organism. The author pays great attention to the role of the reproductive organs and skin. Clearly explains complex terms. The book is equipped with interesting and visual drawings.