This book by Paola Giovetti outlines the life and work of Roberto Assagioli (1888-1974), the father of Psychosynthesis, a psychological and transpersonal current that is meeting with growing interest, primarily because it is a psychology for the healthy person: it is the art of educating oneself and others to build a better world. Roberto Assagioli had a long life full of interests in many fields: besides medicine, psychiatry, and psychology, he dealt with literature, esotericism, social issues, and educational and spiritual problems. Jewish by birth, he always showed extreme respect for all religious traditions, both Western and Eastern. Assagioli contributed greatly to the development of humanistic and transpersonal psychology and was one of the founders of psychosomatic medicine. Paola Giovetti narrates the life of this extraordinary person, the prophet of smiling wisdom, through first-hand documents and the accounts of those who knew him: relatives, friends, colleagues, students, collaborators; and she draws a broad and comprehensive picture of his thought, which is addressed to the person of the 21st century and can help us to truly become, as Assagioli himself said, "God's collaborators."