I'm glad I bought Dr Kaveh Farrokh's book on Anciewnt Persia at War, but I'm even more glad that I got it cheap at a flea market. I had been hoping for something with in-depth treatment of the latest research in organization, tactics, arms etc but the book contains very little on any of these topics. It does however contain interesting speculation on the impact of Iranian culture and language on the world (I had no idea there was a Persian colony in Italy in the 5th C) as well as recounting every Persian king in a 1,000 years (and usually which member of their familiy killed them) and a brief mention of virtually every campaign with some information on battles where available.
Unfortunately for my purposes, while the author takes a stab at weapons in a vague way though he seems to lack real understanding of arms and armour and seems to have little sense of the importance of discipline, command structure, generalship, formations, tactics and so forth. For example the Greek vs Persian clash is seen purely in terms of armour and defeats of Sassanian cavalry at the hands of the Hephthalites appears to be attributed in large part to the latter's method of suspending their sword sheathes by two straps instead of one, and so forth.
Useful background reading but no real use on the tabletop.