I know some of you read Osprey's books, and I've seen it mentioned some in past posts, but I wanted to ask which ones you all think are best regarding empire armies?
My army is (will be) an Ostermark based army with a lot of Ulric fluff in it, so if there are any Osprey books which lend themself especially well to this, please let me know (I'm not sure whether or not the whole of the Empire is based off the same era/people?)
Empire aside, are there any particular lines that are typically better-done than others? Any especially good books or authors you want to point out?