To understand President Abraham Lincoln, one must understand the extraordinary antislavery speech Lincoln delivered at Peoria, Illinois, on October 16, 1854. This three-hour address marked the turning point in Lincoln's political pilgrimage, dramatically altering his political career and, as a result, the history of America. Though historians and biographers have noted its importance, Lincoln's speech at Peoria has not received the attention it deserves. Lehrman offers a complete examination of the speech that changed the course of our nation.