The Tantric tradition is a unique collection of lesser-known texts, concepts, and meditation practices that are usually made available only to experienced and specially initiated practitioners. The "Vajra World" ( vajradhatu in Sanskrit) is a realm of indestructibility, the level of reality beyond all thought and imagination, all impermanence and change, which a fully realized person knows and inhabits. Used metaphorically, "Vajra World" refers to the traditional culture of Tibet and the unique spirituality that is its secret strength. This work treats the more hidden and esoteric aspects of tantric Buddhism as they take shape in Vajrayana. Topics include: the tantric view of human nature and the external world; the special role of the guru, or tantric mentor; the preliminary practices that prepare the student for full initiation; the major dimensions of Vajrayana practice including visualizations, liturgies, and inner yogas; the tradition of the tulku, or incarnate lama; the lore surrounding the death of ordinary people and of saints; the practice of solitary retreat, and more.