The food of northwest China is the product of history on a frontier. In this area, Chinese civilization has bordered on Mongol, Turkic and other Central Asian cultures. Influences from the Islamic world have been strong. Via the Silk Road and other trade routes, west Asian foods (from Persian melons to coriander) entered China by this route, and Chinese foods (such as soy sauce) went west. In this area, sheep and goats are major sources of meat. Dairy products were once important, and still are in some areas. Central Asian noodle dishes and breads have local forms. A unique opportunity to investigate the history of northwest China and its food is provided by cookbooks and medicine books. Dr. Paul Buell and I are just now bringing out an edition and translation of the book Yin-shan Zheng-yao (Necessary Knowledge of Drinking and Feasting), compiled by Yüan court nutritionist Hu Ssu-hui and published in 1330. Hu was a Turkic-speaker writing in Chinese for a Mongol elite. He included not only Chinese, Mongol and Sinkiang Turkic recipes, but also recipes from Kashmir, Persia, Baghdad, and elsewhere. The book, and others of the period, give us a view of a society even more global and transnational than ours today. It is sometimes forgotten that China was central to a vast transnational social world as early as the Han Dynasty, and was massively involved in world trade by the high T'ang. Building on pre-existing routes of trade and contact, the Mongol empires made possible a vast exchange of people, knowledge, and arts of living. Subsequently, the flow of trade turned away from Central Asia, but contacts remained. The food of western China today - whether of Han Chinese, Hui, or Turkic and Mongol minorities - is still shaped by the long history of the region as a zone of cultural interaction.