1. Do They Miss Me at Home?: The Civil War Letters of William McKnight, Seventh Ohio Volunteer Cavalry edited by Donald C. Maness & H. Jason Combs (Ohio U. Press, 2010).
McKnight campaigned with his fellow mounted Ohioans about a year and a half in Kentucky and Tennessee before being killed in 1864 at the Battle of Cynthiana. Around 100 surviving letters are featured here.
2. Great Things Are Expected of Us: The Letters of Colonel C. Irvine Walker, 10th South Carolina Infantry, C.S.A. edited by William Lee White and Charles Denny Runion (U. of Tenn. Press, 2009).
Part of UT Press's fine Voices of the Civil War series, Walker and editors White and Runion take the reader through the battles of the Army of Tennessee, and, from the publisher's description, apparently the colonel was quite high on Bragg.
3. The Red River Campaign of 1864 and the Loss by the Confederacy of the Civil War by Michael J. Forsyth (McFarland, 2010).
New paperback edition. Forsyth's book is the briefest of the worthwhile introductory studies of the campaign. Not a bad choice for someone just looking for the essentials.