In Tibetan Buddhist traditions, a distinction is made between the practice of medicine (sowa rigpa, i. e., the “science of healing”) and a broad range of nonmedical practices—including rituals, contemplative practices, and alchemy—that may be undertaken to promote health and long life, or to eliminate and impede conditions that cause disease.¹ The subject of this chapter is one such technique: a tantric meditation focusing on a popu lar trinity, the “three deities of longevity.” The meditation, which involves the visualization of consecration by the deities and the absorption of their life-sustaining forces, is introduced within the context of