In 1847 General Winfield Scott boldly led a small but undaunted army from the Mexican coast all the way to the Halls of Montezuma, routing Mexican forces at every turn while pacifying the countryside. Scott's military campaign--America's first ever in a foreign country--helped pave the way for victory in the wider war against Mexico and also posed new challenges for discipline, logistics, and the treatment of civilians. Yet it has remained largely neglected by historians. Timothy Johnson interweaves a compelling narrative of the campaign-including detailed battle replays, terrain descriptions, and eyewitness accounts--with a comprehensive analysis of strategy, operations, and tactical masterpieces that inspired a generation of Civil War generals--like Grant, Lee, and McClellan. Scott developed a sophisticated strategy of moderation to end the war by employing a sword-and-olive-branch approach. Although his army repeatedly won battles against superior numbers as it drove ever deeper into Mexico's interior, Scott paused after each contest to give the enemy an opportunity to sue for peace. And by respecting civilian property and purchasing supplies from the populace, his troops limited local support for guerrillas.