Aion, a major work from Jung's later years, has long been a source of fascination for a wide variety of scholars and thinkers. Presented here are two substantial commentaries on this rich and complex text by two important figures in Jung's life and work: Barbara Hannah and Marie-Louise von Franz. Hannah delivered these lectures in 1957 at the C.G. Jung Institute in Zurich. She addresses each chapter of Aion, providing detailed, in-depth analysis of selected passages, while suggesting resources for further study. Well-paced and thoughtfully planned, she scans the work from beginning to end, illuminating many subtle nuances. In a private interview with Claude Drey in her home during the spring of 1965, Marie-Louise von Franz looks closely at chapter fourteen of Aion-"The Structure and Dynamics of the Self." Published here for the first time, von Franz offers a lively and free-flowing discussion of key passages in Jung's work. This is the first volume in a new series edited by Emmanuel Kennedy-Xypolitas, "Polarities in the Psyche," focusing on the broad theme of the opposites in the psyche. The second volume will be The Archetypal Symbolism of Animals (also from Chiron Publications)."