To understand President Abraham Lincoln, one must understand the extraordinary antislavery speech Lincoln delivered at Peoria 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.

Lincoln opposed any further extension of slavery in the American republic, holding to the Declaration of Independence's universal principle that "all men are created equal." In response to the Kansas-Nebraska Act, Lincoln launched his antislavery campaign, delivering speeches in Springfield and Peoria.

The Peoria address was rigorous, logical, and grounded in historical research. It marked Lincoln's reentry into politics and his preparation for the presidency in 1861. The speech catapulted Lincoln into the national debates over slavery and into national politics for the rest of his life.

Though historians and biographers have noted its importance, Lincoln's speech at Peoria has not received the attention it deserves. Lincoln at Peoria offers a complete examination of the speech that changed the course of our nation.