David Daniels, MD (August 30, 1934–May 26, 2017) was a world-renowned teacher in Enneagram studies, self-help, and personal development and an Adjunct Clinical Professor of Psychiatry and Behavioral Sciences at Stanford University School of Medicine. He was a leading developer of the Enneagram system of nine personality types and authored the best-selling book The Essential Enneagram, featuring the first scientifically
validated Enneagram personality test.

Over his thirty-year private practice, David taught the Enneagram to thousands worldwide, integrating it into clinical practice, workplaces, and rehabilitation settings with compassion. Alongside Helen Palmer, he co-founded The Narrative Enneagram (originally, the Palmer-Daniels Enneagram Professional Training Program), and he was an instrumental co-founder of the International Enneagram Association.

Believing deeply in personal liberation through self-discovery, he developed many simple daily personal development methods, including the Universal Growth Process or 5As for personal transformation and self-mastery. In collaboration with Suzanne Dion, David devoted his final years to writing The Enneagram, Relationships, and Intimacy. David’s great hope was that this insightful book would serve as a guide to understanding personality types, leading to personal, relationship, and global healing.