The U.S. Army Campaigns of the Civil War Series

The U.S. Army Center of Military History recently published a series of brochures (books, really) covering the Civil War period, sixteen volumes beginning with a history of the antebellum army and concluding with the end of Reconstruction. The U.S. Army Campaigns of the Civil War Series titles are sold in hard copy on various online sites but they are government publications so you can also download them for free in PDF format at the bold link above.