The so called 'Kingdom of Prester John' was a Christian power thought to exist in Central Asia at the time of the twelfth-century crusades. At a deeper level, for the steppe peoples it constitutes a distant dynamic which led to the world-shattering rise of Mongol power under Chinggis (Genghis) Khan. The book ranges widely in subject matter, space and time. Christian history and ecological, demographic, social and economic history are all interwoven with the politics, religions and literature of the vast and varied area between European Russia and China from c800 to 1300. The author's views are distinctive and stimulating and are not always accepted by western specialists. But his bold synthesis fills in many of the missing links between histories of Europe and medieval China and makes it possible to think of these vast areas as, in some senses, parts of a greater whole.