This is one of the best single volume studies of a war I have read. McPherson starts at the end of the Mexican War in1847 and follows the chain of events over the next decade that eventually led to the outbreak of the Civil War. The crisis that led to seccession in 1861 is also covered in great detail (over 100 pages).
Once the fighting has started, he provides a clear account of what can be a confusing (or perhaps overwhelming) conflict, taking up two thirds of the volume. Interspersed amongst the battles and campaigns are chapters on the development of emancipation, politics north and south, and Lincoln's plans for post-war America.
For a good view of the war from its causes to the eventual Union victory and the collapse of the Confederacy, this book is hard to beat.
Author: James M. McPherson
Publisher: Oxford University Press (also several reissues)