“Frank Visser has written, arguably, the definitive book on Wilber's philosophy.”"Visser's personal access to Wilber brings warmth and nuance to the presentation, while reference to the works of Wilber's critics ensures balance."CHOICE, Feb. 2004‘I myself have some friendly disagreements with Frank about many of these topics, but I always learn something important from him in our exchanges, and I believe you will, too.’Ken Wilber, Foreword