In tracing out the very crooked story of the history of Central and Eastern Asia, in which we have to deal with a succession of empires founded by a number of races, which have necessarily overrun its more desirable areas, there is only one method of inquiry which seems to be at once safe and fertile. This is to commence with the latest revolutions. To gradually unravel the tangle into which the story has been twisted, by first understanding the latest changes, about which we have abundant evidence, and then to work back to that earlier and more obscure period which must always have a great interest and romance for those who speculate on the origin and early history of our race. This is the method I have ventured to adopt in the series of papers on the Northern Frontagers of China, which I have been permitted, by the favour of the Royal Asiatic Society, to commence in the pages of its Journal, and in which I hope, if allowed, to pass in review the different races who have dominated over Central Asia and China from the earliest times.