research!!! My book on the French army in World War I arrived yesterday. It's not exactly what I need--flipping through the photos, I began to get this idea when I saw about ten pictures of giant guns in a row--but I want to read it anyway. The trick will be making myself skim to find only things useful for this particular novel. I can read it later, in depth.
I also need
this Osprey book. I believe Osprey books are intended mainly for tabletop wargamers, but they are also great for small descriptive details to enrich fiction. Also, it helps me to look at drawings of uniforms and such. It's a pity they aren't common in libraries, or maybe not, since it's such a good reference I'm sure I'll be using it constantly.