An introductory military history of the American Civil War, Shades of Blue and Gray places the 1861-1865 conflict within the broad context of evolving warfare. Emphasizing technology and its significant impact, Hattaway includes valuable material on land and sea mines, minesweepers, hand grenades, automatic weapons, the Confederate submarine, and balloons. The evolution of professionalism in the American military serves as an important connective theme throughout.

Hattaway extrapolates from recent works by revisionists William Skelton and Roy Roberts to illustrate convincingly that the development of military professionalism is not entirely a post-Civil War phenomenon.

The author also incorporates into his work important new findings of recent scholars such as Albert Castel (on the Atlanta campaign), Reid Mitchell (on soldiers' motivation), Mark Grimsley (on "hard war"), Brooks D. Simpson (on Ulysses S. Grant), and Lauren Cook Burgess (on women who served as soldiers, disguised as men). In addition, Hattaway comments on some of the best fiction and nonfiction available in his recommended reading lists, which will both enlighten and motivate readers.