I second Soldiering in the Army of Tennessee by Larry J. Daniel. Good statistical and social study of the rank and file of the army.
As for first hand accounts, The Civil War Memoir of Philip Daingerfield Stephenson, D.D. is also a good one by an enlisted man who served in the AoT throughout most of the war, first in the 13th Arkansas Infantry and later with the Washington Artillery.
One of Cleburne's Command: The Civil War Reminiscences and Diary of Capt. Samuel T. Foster - great account by a company commander in Granbury's Texas Brigade.
Liddell's Record - memoirs of Brig. Gen. John R. Liddell.
A Carolinian Goes to War - memoirs of Brig. Gen. Arthur M. Manigault.
Also a lot of biographies of Patrick Cleburne out there. Stonewall of the West by Craig L. Symonds and Pat Cleburne: Confederate General by Howell and Elizabeth Purdue are two of the best.