IS IT a large chain bookstore in almost any American city, and you will find half the shelves in the U.S. History section (sometimes more) groaning under the weight of books about the American Civil Warmrow upon row of volumes by Bruce Catton, Shelby Foote, ]ames MePherson, and many other distinguished authors. Given this surfeit of offerings, do we really need any more Civil War books? Actually, yes, as Jay Winik amply demonstrates in his thought-provoking book, April 1865: The Month That Saved America.