This article substantiates the importance of Ken Wilber and his work on transpersonal theory to the psychology and spirituality of human development over the past 23 years. Wilber and his work, prior to 1995, continue to attract ardent controversy, particularly outside of the field of transpersonal psychology. The focus of this article is directed to the identification of a few common pervasive misunderstandings based on recent critiques from writers in psychology. Although Wilber's critical style is at times unnecessarily arrogant, the evidence indicates that the critics' interpretations are not often substantiated and tend to become explicitly or implicitly polemical. This trend is the opposite effect of Wilber's stated intentions of his unifying spectrum psychology. This article is divided into three parts: First is Wilber's actual intentions; second, his major theses; and third, his critical style, with a number of summary hypotheses provided for further study to explain the conflicts between Wilber and his critics.