Cells are the foundation of all life. Our body is made up of billions of them: an incredibly complex network that controls everything from movement to memory and imagination. As we age, it is because our cells decline; when we become ill, it is because our cells mutate or cease to function. In his new book, the world-renowned cell and developmental biologist Lewis Wolpert provides a vivid and engaging account of the science that is uncovering the mystery of our existence. He explains how our body works and how organs and organ systems form from the fertilized egg in the embryo. He illustrates how all life has developed from cells. And he explores the science behind topics that are currently highly controversial but rarely truly understood—stem cell research, cloning, and genes.