
Books by Riso and Hudson (The Enneagram Institute):
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The Wisdom of the Enneagram: The Complete Guide to Psychological and Spiritual Growth for the Nine Personality Types, by Don Richard Riso and Russ Hudson (1999)
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Personality Types: Using the Enneagram for Self-Discovery, by Don Richard Riso with Russ Hudson (1996)
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Understanding the Enneagram: The Practical Guide to Personality Types, Revised Edition, by Don Richard Riso and Russ Husdon (2000)
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Enneagram Transformations: Releases and Affirmations for Healing Your Personality Type, by Don Richard Riso (1993)
Website: enneagraminstitute.com

Books by Palmer and Daniels (The Narrative Enneagram):
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The Enneagram: Understanding Yourself and the Others in Your Life, by Helen Palmer (1991)
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The Enneagram in Love & Work: Understanding Your Intimate & Business Relationships, by Helen Palmer (1995)
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The Essential Enneagram: The Definitive Personality Test and Self-Discovery Guide, by David Daniels, M.D. and Virginia Price, Ph.D. (2009)
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The Enneagram, Relationships and Intimacy: Understanding One Another Leads to Loving Better and Living More Fully, by David Daniels, M.D. and Suzanne Dion (2018)
Website: narrativeenneagram.org
Website: enneagram.com (Helen Palmer's website)
Website: drdaviddaniels.com (Dr. David Daniel's website)
Website: theenneagramatwork.com (Peter O'Hanrahan's website)


Books by Ginger Lapid-Bogda, Ph.D. (The Enneagram in Business): (Excellent for organizational applications)
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The Art of Typing: Powerful Tools for Enneagram Typing, by Ginger Lapid-Bogda, Ph.D. (2018)
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Bringing Out the Best of Yourself at Work: How to Use the Enneagram System for Success, by Ginger Lapid-Bogda, Ph.D. (2004)
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What Type of Leader are You: Using the Enneagram to Identify and Grow Your Leadership Strengths and Achieve Maximum Success, by Ginger Lapid-Bogda, PhD. (2007)
Website: theenneagraminbusiness.com
Books by Beatrice Chestnut, Ph.D.
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The Complete Enneagram: 27 Paths to Greater Self-Knowledge, by Beatrice Chestnut, Ph.D. (2013)
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The 9 Types of Leadership: Mastering the Art of People in the 21st Century Workplace, by Beatrice Chestnut, Ph.D. (2017)
Website: beatricechestnut.com

Books from the Diamond Approach® perspective:
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The Spiritual Dimension of the Enneagram: Nine Faces of the Soul, by Sandra Maitri (2000)
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The Enneagram of Passions and Virtues: Finding the Way Home, by Sandra Maitri (2005)
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Facets of Unity: The Enneagram of Holy Ideas, by A.H. Almaas (2000)
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Keys to the Enneagram: How to Unlock the Highest Potential of Every Personality Type, by A.H. Almaas (2021)
Website: sandramaitri.com (Sandra Maitri)
Website: diamondapproach.org (A.H. Almass)

Books by Susan Rhodes:
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Archetypes of the Enneagram: Exploring the Life Themes of the 27 Enneagram Subtypes from the Perspective of Soul, by Susan Rhodes (2010)
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The Integral Enneagram: A dharma-oriented approach for linking the nine personality types, nine stages of transformation & Ken Wilber's Integral Operating System, by Susan Rhodes (2013)
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The Positive Enneagram: A New Approach to the Nine Personality Types, by Susan Rhodes (2009)
Website: enneagramdimensions.net