The American Civil War was the deadliest in American history, with estimates of 600,000 or more soldiers killed in action, and an unknown number wounded. Disease took many more lives within the military of both sides. Four of the most prominent generals wrote their memoirs after the war: Grant, Sherman, Longstreet, and Sheridan related their experiences in outstanding fashion, including numerous personal stories and describing their campaigns in clear and highly intelligent prose. This history includes excerpts from their memoirs, which are in the public domain. This work also narrates the life of Robert E. Lee, with short inclusions from Douglas Southall Freeman's Pulitzer Prize winning history, Lee. The biographies of the five generals are developed in an intertwined fashion, drawing heavily on their writings and on related memoirs of some of their prominent aides, such as Horace Porter, Moxley Sorrel, and John B. Gordon. There are short excerpts from other sources such as Jeffery D. Wert, and Adam Badeau. Four of these five men were key players in the Mexican-American War, and all were at the mainstream of the American Civil War. In the latter, they sometimes faced each other in battle, therefore some battles are portrayed from multiple viewpoints. The memoirs of Longstreet, Sheridan, Sherman, and Grant are invaluable contributions to American history. Their insights present a clear and comprehensive picture of those troubled times which have greatly influenced today's America.