It was about 12:30 p.m. on this day in 1963 that President John F. Kennedy was fatally shot while riding in a motorcade in Dallas, Texas. It was the only successful assassination of an American president carried out in the last hundred years, and the only presidential assassination ever caught on film. Almost every American alive at the time remembers where they were when they heard the news. Walter Cronkite cried when he made the announcement that the president was dead.

The reason Kennedy was in Texas was that he was already gearing up for the election in 1964, and he wanted to meet the two Democrats who were planning to run for governor of Texas. The secret service wanted Kennedy and his wife to travel directly from the airport to the Dallas Trade Mart, where he was scheduled to make a speech. But Kennedy and Johnson had decided that it would be good publicity if he rode through Dallas so that reporters could cover the fact that a huge crowd had applauded the president.

Thousands of people turned out to watch the motorcade through Dealey Plaza. The president and his wife were in an open limousine, sitting behind the then governor of Texas, John Connolly, and his wife, Nellie. As they drove through the plaza, Nellie Connolly said, "Mr. President, you can't say that Dallas doesn't love you." He replied, "No, you certainly can't." Those were the last words he ever spoke. Seconds later, people in the crowd heard shots being fired, and two of the bullets hit Kennedy, first in the throat and then in the head.

The national TV networks interrupted all programming to bring several days of coverage of the events. A young man named Lee Harvey Oswald was arrested 90 minutes after the murder took place. Two days after his arrest, Oswald was being transferred to jail, in front of TV cameras, when a local nightclub owner named Jack Ruby pulled out a gun and shot him. It was one of the only times in American history that a man was murdered on live television.

There was wild speculation about who might have been behind the assassination, especially after the assassin himself was assassinated. Chief Justice Earl Warren presided over a presidential commission to investigate the event. The Warren Commission's report filled 27 volumes with about 10 million words. It included the transcripts of 25,000 FBI interviews, 1,500 Secret Service interviews, the testimony of 552 witnesses who appeared before the commission itself, as well as photos and related documents.

The writer Don DeLillo, who wrote the novel Libra (1988) about the Kennedy assassination, said of the Warren Report, "Everything is here. Baptismal records, report cards, postcards, divorce petitions, canceled checks, daily timesheets, tax returns, property lists, postoperative X-rays, photos of knotted string, thousands of pages of testimony. ... It is all one thing, a ruined city of trivia ... the Joycean Book of America."

The Warren Commission concluded in 1964 that the accused assassin Lee Harvey Oswald acted alone and that Jack Ruby had also acted alone. But even before the commission's report was released, books were already being published suggesting various conspiracy theories. Today, there have been more books written by amateur historians about the Kennedy assassination than any other event in history.

The various conspiracy theories implicate a right-wing conspiracy within the U.S. government, a group of right-wing dissidents, anti-Castro Cubans and their supporters, left-wing pro-Castro Cubans, or the Mafia. Today, less than half of all Americans believe the Warren Commission's conclusion that Oswald acted alone.