Here are a couple of recent titles that have been sent along by publishers.
1) From Simon & Schuster comes the new book from Fergus M. Bordewich titled America's Great Debate: Henry Clay, Stephen A. Douglas, and the Compromise That Preserved the Union. Read more about the book on the publishers website here. There is also a three minute video of the author briefly discussing the time frame.
2) From LSU Press comes Rebels on the Border: Civil War, Emancipation, and the Reconstruction of Kentucky and Missouri written by Aaron Astor. The publisher has a nice information page here.