Union Major-General William Tecumseh Sherman's telegraph--"Atlanta is ours, and fairly won"--had a huge impact on the course of the Civil War. The culmination of a four-month campaign in the Western Theater, it propelled Abraham Lincoln to reelection.

Atlanta marked the beginning of the final Confederate struggle for survival. Union forces under Sherman lined up against Joseph E. Johnston's Army of Tennessee. The superior Union numbers forced the Confederates into a series of delaying actions from entrenched positions. When John Bell Hood replaced Johnston, the Confederates launched...