How did we become who we are? Why do we have two arms and legs, but only one head? Why is the human body symmetrical, but at the same time its halves are not completely identical? Why are identical twins' fingerprints not the same? How did our brain develop and what is consciousness? Why are we mortal and what is the biological meaning of this? People have asked themselves similar questions since ancient times. Even now, with the modern development of science, the fundamental principles due to which such a complexly organized organism is formed from a single fertilized egg, consisting of many molecular structures that interact with each other, have their own life cycle, are capable of regeneration and self-development. “This is based on the principle of central adaptive self-organization,” says modern biology. But what is this principle? Jamie Davis has done a great job of adapting the most complex scientific material to a level understandable to the general reader. In a fascinating and ironic way, providing his story with more than 80 illustrations, the author invites the reader on a journey through all aspects of human biological development - from conception to death. The latest advances in embryology, genetics, physics, neuropsychology will allow us to learn more about stem cells and protein metabolism, differences between chromosomes and gene functions, neural connections and other important factors influencing the internal evolution of humans.