I'm still in Missouri working hard on Guerrilla Tactics of the American Civil War for Osprey Publishing, and I must say the most challenging aspect of this project is the artwork. Osprey is famous for their heavily illustrated military histories, and anyone who works for them quickly finds out that the writing is only half the battle. Not only do I have to find fifty to sixty photos, but I also have to give complete references for eight color plates that will be painted by an artist.
The photos are easy; I've collected photos for all of my earlier books and know where to look. The artist's references are a big job, though. I have to thoroughly describe the scene as well as all uniforms, equipment, weapons etc., and it all has to be accurate from boots to buttons. When I signed the contract my editor said, "Don't assume the artist has any knowledge of the period." Actually the Osprey artists very knowledgeable, but this is a good mindset to be in when making the references. The more detail, the better.
It's an interesting challenge to basically design eight paintings, and not something I thought I'd be doing as a writer. It just goes to show that writing isn't all about putting words onto paper!