July 1863 was a momentous month in the Civil War. News of Gettysburg and Vicksburg electrified the North and devastated the South. Sandwiched geographically between those victories and lost in the heady tumult of events was news that William S. Rosecrans’s Army of the Cumberland had driven Braxton Bragg’s Army of Tennessee entirely out of Middle Tennessee. The brilliant campaign nearly cleared the state of Rebels and changed the calculus of the Civil War in the Western Theater. Despite its decisive significance, few readers even today know of these events. The publication of Tullahoma: The Forgotten Campaign that Changed the Course of Civil War, June 23 - July 4, 1863 by award-winning authors David A. Powell and Eric J. Wittenberg, forever rectifies that oversight. On June 23, 1863, Rosecrans, with some 60,000 men, initiated a classic campaign of maneuver against Bragg’s 40,000. Confronted with rugged terrain and a heavily entrenched foe, Rosecrans intended to defeat Bragg through strategy rather than bloodshed by outflanking him and seizing control of Bragg’s supply line, the Nashville & Chattanooga Railroad, at Tullahoma and thus force him to fight a battle outside of his extensive earthworks. It almost worked. The complex and fascinating campaign included deceit, hard marching, fighting, and incredible luck—both good and bad. Rosecrans executed a pair of feints against Guy’s Gap and Liberty Gap to deceive the Rebels into thinking the main blow would fall somewhere other than where it was designed to strike. An ineffective Confederate response exposed one of Bragg’s flanks—and his entire army—to complete disaster. Torrential rains and consequential decisions in the field wreaked havoc on the best-laid plans. Still Bragg hesitated, teetering on the brink of losing the second most important field army in the Confederacy. The hour was late and time was short, and his limited withdrawal left the armies poised for a climactic engagement that may have decided the fate of Middle Tennessee, and perhaps the war. Finally fully alert to the mortal threat facing him, Bragg pulled back from the iron jaws of defeat about to engulf him and retreated—this time all the way to Chattanooga, the gateway to the rest of the Southern Confederacy. Powell and Wittenberg mined hundreds of archival and firsthand accounts to craft a splendid study of this overlooked campaign that set the stage for the Battles of Chickamauga and Chattanooga, the removal of Rosecrans and Bragg from the chessboard of war, the elevation of U.S. Grant to command all Union armies, and the early stages of William T. Sherman’s Atlanta Campaign. Tullahoma—one of the most brilliantly executed major campaigns of the war—was pivotal to Union success in 1863 and beyond. And now readers everywhere will know precisely why.