First published in German in 1951, this is one of the major works of Jung's later years. Its central theme is the symbolic representation of the psychic totality through the concept of the Self, whose traditional historical equivalent is the figure of Christ. "Aion contains some of Jung's most advanced thinking on the integrative principles of the psyche, and on the relation of matter to the symbolic processes of the collective unconscious. This is difficult ground to explore, but those who attempt the journey will find that their horizons have been surprisingly widened."