What defines humanity? The question of what the soul or psyche is has been explored by humans for over two thousand years. This volume provides an overview of the history of psychology and illustrates how it has evolved into the science we know today across various epochs. The development of the field is presented starting from the philosophy of antiquity, through the prevailing concepts of humanity in the Middle Ages and early modern period, to the current state. It is related to the significant cultural movements of each era. In this way, the present goals, methods, and self-understanding of psychology can be viewed and assessed from a new perspective. The individual chapters introduce the central ideas and theories of each period.