The Complex Theory developed by Carl Gustav Jung, along with his insights on emotions, imagination and the creative power of the psyche have paved the way for current research on the effects of placebos and the interactions between the psyche and the immune system. Jung’s concept of the mind-body-­relationship helps overcome misconceptions about root causes, guilt, and blame. It is important to note that the prevention and treatment of physical diseases are impossible without embracing the human psyche, as exemplified by numerous case studies from psychotherapeutic practice that serve to illustrate the content of this book.