I watched Valkyrie the other day and one quote greatly intrigued me about ancient warfare. That one Nazi Reserve commander guy said "They'd execute people for things like this in the ancient greek militaries" or something along the lines of that. I've been curious about it for a while, watching 300 and all that but I'd like to know how the ancient Greek, Roman, and possibly Israelite armies were structured and how they operated, tactics, and so on. Do you guys know of any good books to turn to about this kinda thing?