Fort Donelson, Tennessee, guarding the Cumberland River, became the site of the first major Confederate defeat in the Civil War. Victory at Donelson started Brigadier General Ulysses S. Grant on his road to Appomattox and the White House. His cool judgment under pressure saved the day after the Confederates threatened to break his troop lines, yet errors by his opponents handed him a victory that he did not fully earn on his own. Possession of the better part of two states vital to the South depended on the outcome of the battle at Fort Done ....