Southern Storm: Sherman's March to the Sea by Noah Andre Trudeau (HarperCollins, Aug 2008). Eric mentioned a while back that Trudeau was working on a Sherman's March project, but this is the first public notice I've come across. There is certainly plenty of room for a full study.
Lincoln's Darkest Year: The War in 1862 by William Marvel (Houghton Mifflin, July 2008). I think I heard or read somewhere that Marvel was planning a three volume series, so I wonder if this is Part 2. This one is from the same publisher, anyway. Marvel's earlier study [reviewed here] received a generally mixed reception, but I find his often provocative views to be always worth a listen.