1. Crossroads of Conflict: A Guide to Civil War Sites in Georgia by Barry L. Brown and Gordon R. Elwell (Univ of Georgia Pr, 2010).
Organized by region, this book covers 350 sites across the state, supplemented with over 200 photographs, paintings, drawings, and maps, the majority in color. At the rear of the book is a table of GPS coordinates for each location. It's a nicely put together reinforced softcover with thick glossy pages at a very reasonable price.
2. The Battle of Glorieta Pass: The Colorado Volunteers in the Civil War March 26, 27, 28, 1862 by William C. Whitford (Rio Grande Press, 1991).
Published in 1906 after the author's death, William Clarke Whitford's manuscript was the first substantial work on the Glorieta battle. The 1991 edition added a new index (Whitford's original lacked one) and a 22 page appendix comprising a map series, battle analysis, and detailed OBs by Burt Schmitz. The edition is not scarce, and, in my opinion, the additional material alone is worth the modest purchase price.