1. The Massachusetts Andrew Sharpshooters: A Civil War History and Roster by Alden C. Ellis, Jr. (McFarland, 2012).
Everyone knows about Berdan's Sharpshooters, but I recall during my Peninsula Campaign order of battle research coming across several company-sized sharpshooter units that I'd never heard of before. The Andrew Sharpshooters from Massachusetts was one and now they have their own complete history and roster.
2. "Bully for the Band!": The Civil War Letters and Diary of Four Brothers in the 10th Vermont Infantry Band by Charles George, Herbert George, Jere George, and Osman George; edited by James A. Davis (McFarland, 2012).