More to explore:
Army Rank Cheatsheet
US Military Rank Chart
United States Military Rank Chart
Military Rank Chart - Great little cheat sheet!
Military Rank Chart: Very handy if you have ancestors or current relatives in the military. I had all but the Marines mastered with Army, Navy, and Air Force bases nearby when I was in elementary school, but I need a refresher. There are web sites where you can find what the uniforms were like, and so on.