The military is a very cool world to write about. I went down to Ft. Benning, Ga., for military training, and I learned a lot about soldiers and officers and why they joined up and what their life has been like.
I enjoyed doing the gag covers better than the story ones because they were usually simpler. A cover based on an incident in the plot took a great deal of staging to tell a little story that was still part of the book. And it had to make sense on its own.