Shelby Foote's recent death has propelled sales of his Civil War.
At Amazon, the three volume paperback set ranked #343 as I post this, a phenomenal place for a boxed set and the highest place I have ever seen a Civil War tome attain. (By comparison, the steady-selling paperback edition of Battle Cry of Freedom is currently at #4,794.)
Barnes & Noble have moved Foote to the top of their results for "Civil War" searching, but the paperback set there ranks at 17 when ACW titles are sorted by bestseller status. It is in third place if you sort out noise like Huckleberry Finn, being outranked only by Gingrich's and Shaara's novels.