This book examines metaphysical experimentation that lies at the center of some of the most influential intellectual and religious movements in modern Iran. In particular, it investigates encounters with occult specialists, séances with the souls of the dead, new forms of exorcism and healing, and appeals to marvelous mystical powers. Focusing on rationalization since the late nineteenth century, and especially under the Islamic Republic, the book argues that the metaphysical inquiries of occult experimentalists and spiritual explorers like the Cosmic Mystics are best understood in terms of attempts to rationalize the “unseen” (gheyb)—that is, to grasp phenomena like sorcery and jinn possession in reasoned, scientific, nonsuperstitious terms. The book also explores how metaphysical experimentation is affected by economic liberalization, the dominance of modern technoscience, and the increasing bureaucratization of life under the Islamic Republic.