John Michael Greer is a prolific author writing on diverse topics like peak oil, nature-based economics and, of course, druidry, because he is the Grand Archdruid of the Ancient Order of Druids in America. His knowledge is vast and his presentation makes even complex topics understandable and compelling. His books include The Ecotechnic Future: Envisioning a Post-Peak World and The Wealth of Nature: Economics as if survival Matter.