In the 19th century, the Scottish writer Thomas Carlyle famously wrote, "The history of the world is but the biography of great men," popularizing the "Great Man" theory that the course of history is shaped by a select few heroic individuals. While historians and others continue to debate the accuracy of the Great Man theory of history, there is no question that the course of history is permanently altered by decisive moments in time, where a different result would have produced drastically different outcomes. Charles River Editors' Decisive Moments in History examines the events that changed history forever and set the world down the path it finds itself on today.

Until April 14, 1865, John Wilkes Booth was one of the most famous actors of his time, and President Abraham Lincoln had even watched him perform. But his most significant performance at a theater did not take place on the stage. That night, Booth became one of history's most infamous assassins when he assassinated President Lincoln at Ford's Theatre in Washington, DC. Booth was a member of the prominent 19th century Booth theatrical family from Maryland and, by the 1860s, was a well-known actor. But he was also a confederate sympathizer who dabbled in espionage, and he was increasingly outraged at the Lincoln administration. Although Robert E. Lee's Army of Northern Virginia had surrendered days earlier, Booth believed the war was not yet over because Confederate General Joseph E. Johnston's army was still fighting the Union Army, so he and his group of conspirators plotted to kill Lincoln and other top officials in a bid to decapitate the federal government and help the South.

Perhaps not surprisingly, the actor's flair for the dramatic came at a cost to the plot.