It's kind of dull that I just started reading a great big book of Islamic history again (got it out from the library for a second time) that I've mentioned a number of times here.
I did however just finish reading Combat Sports in the Ancient World, by Michael Poliakoff, about boxing, wrestling, pankration ("ultimate fighting") and stick (staff) fighting in the ancient world. Pretty good read, although I wished there'd been more about the Egyptian stick fighting.
I just got out another book which looks like it'll be interesting (in its own right, and as campaign inspiration material): Samarkand and byond: a history of desert caravans, by James Wellard. Looks really neat... it's got maps with the main caravan routes (the Silk Road, the salt caravans across the Sahara, into Arabia for spices, etc).