This book details the history of the idea of psychological development over the past two millennia. The developmental idea played a major part in the shift from religious ways of explaining human nature to secular, modern ones. In this shift, the 'elect' (chosen by God) became the 'normal' and grace was replaced by cognitive ability as the essentially human quality. A theory of psychological development was derived from theories of bodily development, leading scholars describe human beings as passing through necessary 'stages of development' over the lifespan. By exploring the historical and religious roots of modern psychological concepts and theories, this book demonstrates that history is a method for standing outside psychology and thereby evaluating its fundamental premises. It will spark new interest in the history, sociology and philosophy of the mind sciences, as well as in the rights of children and developmentally disabled people.