This is the fourth volume of collected essays published by AHP. Volume 21 features articles on English language education and globalization; New Year celebrations in A mdo; hail prevention rituals and practitioners; pyramid schemes on the Tibetan Plateau; Tibetans and Muslims in northwest China; sacred dairies, dairymen, and buffaloes of the Nilgiri Mountains in South India; an A mdo family's annual income and expenses; vernacular architecture; and cultural change in the context of female coming of age rituals in A mdo. Volume 21 also contains six short stories and ten reviews.