I didn't read that as necessarily war being the theme, more as a way of splitting up periods. And of course songs around a war aren't just songs about the fightig, they're about what's happenimg in between the fighting, and back home. You could say Little Women is the best book about the American Civil War.

"Carry it On" by Pete Seeger and Bob Reiser is the best song-and-picture book about American history I've ever seen. And it's got a good bibliography as well.