In introducing the "schools" of Tibetan and Mongolian Buddhism, several different phenomena in the formation of religious traditions must be distinguished. One may speak, for instance, of distinct orders or sects (chos lugs, or more specifically rang rkang btsugs pa'i chos brgyud), religious traditions that are set apart from others by virtue of their institutional independence, that is to say, whose unique character is embodied outwardly in the form of an independent hierarchy and administration, independent properties, and an identifiable membership of some sort. Such corporate religious bodies are of great importance in the Tibetan religious world, but they must not be confounded with lineages (brgyud pa), continuous successions of spiritual teachers who have transmitted a given body of knowledge over a period of generations but who need not be affiliated with a common order. Lineages may be highly specific, for instance...