The Role of Union Cavalry in the Atlanta Campaign
Major Robert Blake Leach
Master's Thesis, University of Kentucky, 1980; pub. Ft. Leavenworth, 1994.
I go back to this thesis quite often and have used it as a source. It is a helpful summary and is easy to read (clear, well written). Among other things, it makes a significant point about technological advances during the Civil War, which began to impact the traditional role of cavalry.