- The Bodhisattva Question: Krishnamurti, Rudolf Steiner, Annie Besant, Valentin Tomberg, and the Mystery of the Twentieth-Century Master
- Light for the New Millennium: Rudolf Steiner's Association With Helmuth and Eliza Von Moltke : Letters, Documents and After-Death Communications
- In the Sign of Five 1879-1899-1933-1998-Today: The Five Spiritual Events, Tasks and Beings of the First Half of the Age of Michael
- Representative Men: In the Light of Anthroposophy with a Chapter on the Twelve Worldviews
- Clairvoyance and Consciousness: The Tao Impulse in Evolution