Mainland Southeast Asia comprises the modern countries of Thailand, Laos, Cambodia, Burma (Myanmar), and Vietnam, as well as parts of Malaysia and Yunnan province in China. However, it is more useful to examine the Buddhism of the region in terms of language group or culture than of these relatively recent nation-states. This Buddhism is in no sense monolithic, and one may reasonably speak of "Buddhisms" of the Thai, Lanna Thai, Shan, Lao, Khmer, Mon, Arakanese, and Burmese. These Buddhisms are "Theravādin" in the sense that they are transmitted by monastic orders that descend from Sri Lankan ordination lineages, and in the sense that these orders are custodians of a foundational literature, the Pali canon. The use of Pali, the classical Indic language of Theravāda Buddhism, links the Buddhisms of the region and gives them common access...