1. Financial Fraud and Guerrilla Violence in Missouri's Civil War, 1861-1865 by Mark Geiger (Yale Univ Pr, 2010).
The promotional blurbs I've read seem to be a bit all over the place in terms of the book's main thrust, but the heart of it seems to be a shady financial scheme to transfer funds from Missouri banks to secessionist forces. The author demonstrates how the fraud fueled guerrilla violence and helped shape the state's future. Sounds pretty pathbreaking.
2. Iowa's Martyr Regiment by David Wildman (Camp Pope Pub, 2010).
I mentioned this one recently (at this post).
3. Kansans At Wilson's Creek Soldiers' Letters From the Campaign for Southwest Missouri by Richard Hatcher and William G. Piston (Wilson's Creek NB Foundation. 1993).
Undoubtedly, much of this material made its way into Hatcher and Piston's excellent Wilson's Creek campaign study.