A great psychiatrist and the founder of an original school of psychoanalysis, Jung, despite always being an empiricist, could not avoid engaging in dialogue with philosophy while also being committed to his inner truth and that "reality of the soul" that permeates life and the world. As the creator of the concept of the collective unconscious, he saw the life of individuals as the task of achieving a conscious and active expression of the seeds that lie in that ancient unconscious layer, which tries to actualise itself in everyone's life. For this reason, his thought was not limited to individual psychology, which he also delved deeply into, but broadened to include anthropology, the analysis of myths, and even natural sciences, namely quantum physics, with which he interacted in formulating his concept of synchronicity. This book examines the many aspects of his rigorous and passionate intellectual adventure, developing its most modern theoretical features and critically analysing the formulations that sometimes caused it to be misunderstood.