Book excerpt: You are the only you. You are special--one of a kind. Do you know when you began to exist as a human being? This picture book is a celebration of your humanity and your human development--one of the most extraordinary phenomena in all of science and nature. When You Became You features glorious illustrations and the biological science of human embryology to introduce the continuum of human life. It takes you on a scientific journey through the stages of a human being's life. Your boundless capacity as a human being began when you did--even before you were born--and persists for the duration.