Out-of-Body Exploring: A Beginner’s Approach, Hampton Roads, 2004

Outbreak of Peace: Satsung with Isaac Shapiro

Overtones and Undercurrents: Spirituality, Reincarnation, and Ancestor Influence in Entheogenic Psychotherapy, Park Street Press, 2017

Parallel Universes: The Search for Other Worlds

Paranormal: My Life in Pursuit of the Afterlife (with Paul Perry), HarperOne, 2012

Perfect Ending: A Conscious Approach to Dying and Death / Inner Traditions, 1998

Not Crazy, Just Enlightened: A Voyage of the Soul, Galde Press, 2000

Occupy Spirituality: A Radical Vision for a New Generation (Sacred Activism), (with Adam Bucko) North Atlantic Books, 2013

Occupy Spirituality: A Radical Vision for a New Generation (Sacred Activism), (with Matthew Fox), North Atlantic Books, 2013

On the Edge of Reality: Hidden Technology, Powers of the Mind, Quantum Physics, Paranormal Phenomena, Orbs, UFOs, Harmonic Transmissions, and Crop Circles (with Colin Andrews), New Page Books, 2013