The vivid, behind-the-scenes story of perhaps the most consequential political moment in American history—Abraham Lincoln’s history-changing nomination to lead the Republican Party in the 1860 presidential election.

Illinois lawyer Abraham Lincoln had a record of political failure. In 1858, he had lost a celebrated Senate bid against incumbent Stephen Douglas, his second failed Senate run, and had not held public office since one term in Congress a decade earlier. As the Republican National Convention opened in mid-May 1860 in Chicago, powerful New York Senator William Seward was the overwhelming favorite for the presidential nomination, with notables like Salmon Chase and Edward Bates in the running. Few thought Lincoln stood a chance—though stubborn Illinois Circuit Judge David Davis had come to fight for his friend anyway.

Such was the political landscape as Edward Achorn’s The Lincoln Miracle opens on Saturday, May 12, 1860. Chronicling the tense political drama as it unfolded over the next six days, Achorn explores the genius of Lincoln’s quiet strategy, the vicious partisanship tearing apart America, the fierce battles raging over racism and slavery, and booming Chicago as a symbol of the modernization transforming the nation. Closely following the shrewd insiders on hand, from Seward power broker Thurlow Weed to editor Horace Greeley—bent on stopping his former friend, Seward—Achorn brings alive arguably the most consequential political story in America’s history.

From smoky hotel rooms to night marches by the Wide Awakes, the new Republican youth organization, to fiery speeches on the floor of the giant convention center called The Wigwam, Achorn portrays a political climate even more contentious than our own today, out of which the seemingly impossible long shot prevailed, to the nation’s everlasting benefit. As atmospheric and original as Achorn’s previous Every Drop of Blood, The Lincoln Miracle is essential listening for any Lincoln aficionado as it is for anyone who cares about our nation’s history.