"Oriental Armour", by H. Russell Robinson (1967, reprinted 2002):
http://www.amazon.com/exec/obidos/tg/detai...=books&n=507846Very dated, but still probably the best English-language book that deals with Chinese armour (other than the rather skimpy but well-illustrated Chris Peers titles from Osprey). Some views are very questionable in light of newer research - for example, that the Chinese mainly used scale rather than lamellar, and that the Tang used alot of horse armour. But if you can also read the newer books in Chinese, it's a good source of comparison to see how dismal the state of the field in the West remains.
Best source in Chinese - "Zhongguo Gudai Junrong Fushi", by Liu Yonghua (1995, now out in a much cheaper and smaller paperback edition):
http://www.amazon.com/exec/obidos/tg/detai...=books&n=507846See also the four books by Chris Peers in the Osprey Men-at-arms Series:
http://www.amazon.com/exec/obidos/tg/detai...=books&n=507846Other Osprey titles worth a look are David Nicolle's "Attila and the Nomad Hordes" (covers a bit on Xiongnu, Northern Wei, Rouran, Uyghurs, Karakhitan, etc.), Antony Karasulas' "Mounted Archers of the Steppe", Ian Heath's "The Taiping Rebellion", Philip Jowett's "Chinese Civil War Armies, 1911-1949", and Stephen Turnbull's titles on Siege Weapons of the Far East (2 parts), the Mongols, the Mongol Warrior, and Fighting Ships of the Far East (2 parts).
Chris Peers has written a kind of introductory history (non-academic) to Chinese military history entitled "Warlords of China":
http://www.amazon.com/exec/obidos/tg/detai...=glance&s=booksNot very satisfactory, and does not have colour illustrations, but worth a browse if you see it in the bookshop (yes, the Amazon.com review was written by me).