Volume One of The Collected Works of Ken Wilber includes:

• The Spectrum of Consciousness (1977)—one of the founding texts of transpersonal psychology—introduces the full-spectrum model, showing how the psychological systems of the West can be integrated with the contemplative traditions of the East.
• No Boundary: Eastern and Western Approaches to Personal Growth (1979) is a simple yet comprehensive guide to psychologies and therapies available from both Western and Eastern sources.
• Several important early articles: "The Psychologia Perennis," "Are the Chakras Real?" and "Where It Was, I Shall Become."