Chattanooga (Then & Now: Tennessee) Rob Clifton wrote this tome which features pictures from the past and (normally) the same view in the present. Originally published in 2007, the pictures show how the city has advanced since the "good old days."
The Shipwreck of Their Hopes: THE BATTLES FOR CHATTANOOGA For the ease with which Wiley Sword tells the story of the Battle of Chattanooga, Peter Cozzens retells with incredible detail. Chances are you will want to reread this book to get the whole story.
Chattanooga: A Death Grip on the Confederacy by James Lee McDonough. Starting with the defeat of Rosecrans' forces during the Battle of Chickamauga, McDonough carries us through both military and policital action leading up to the battle, and details complex situations with ease.