Books on General Forrest The Confederacy's Greatest Cavalryman: Nathan Bedford Forrest Brian Steel Wills covers much more than the cavalryman's incredible feats on the field of battle. He also provides the most thoughtful and complete analysis of Forrest's hardscrabble childhood in backwater Mississippi; his rise to wealth in the Memphis slave trade; his role in the infamous Fort Pillow massacre of black Union soldiers; his role as founder and Grand Wizard of the first Ku Klux Klan; and his declining health and premature death in a reconstructing America.
That Devil Forrest: Life of General Nathan Bedford Forrest by John Wyeth. This was written by one of Forrest's men. The book is definitely pro-Forrest, but more importantly, written in the prose of a bygone era. Unless you are used to reading older books, I would recommend one that is a little more contemporary.
Nathan Bedford Forrest: A Biography by Jack Hurst. It seems that this is the book most fans of General Forrest like the most, probably because of Hurst ability to present some of the seamier episodes in a positive light, at least for the general.