VAJRADHARA (Tib., Rdo rje chang [Dorje chang]; Mongolian, Ochirdana) is, in the last stages of Indian Tantric Buddhism and in the continuing Tibetan traditions, the distinct embodiment of the highest state of being, the primordial Ādibuddha, and the revealer of all the Tantras. But he was not always thus, for in the beginning in India Vajradhara was simply another name for Vajrapāṇi (Tib., Phyag na rdo rje [Chagna dorje]), both bodhisattva and deity. One can explain this development as the logical expansion of the tiny terminological difference between the less concrete "bearer (-dhara) of the vajra" and the unambiguous "vajra in hand." Vajrasattva (Tib., Rdo rje sems dpa' [Dorje sempa]; Chin., Wo tzu lo sa tsui; Jap., Kongosatta) further complicates the historical picture. "Vajra being" was at first another early synonym for Vajrapāṇi, then both a synonym for Vajradhara and a distinct deity in his...