The Complete Roman Army
Oh my gosh, what a cool book is The Complete Roman Army by Adrian Goldsworthy! Minutely detailed, lavishly illustrated, the only thing that disappointed me was the sad awareness of how much pleasure this book would have given my 14-year-old self had it been available then! The drawings of the evolution of the Roman infantry helmet would alone have justified the expenditure of a week's pocket money.
This is not a narrative, but rather a section by section beautifully produced study of such topics as fortifications, pay scales, tactics, artillery, and the evolution of the Roman military system from republican militia to imperial professional force to late imperial field and frontier troops. Whatever is the opposite of chick lit, this outstanding work of analytic history is it.