In modern times, multiple conspiracy theories concerning the assassination of John F. Kennedy in 1963 have emerged. Vincent Bugliosi estimated that over 1,000 books had been written about the Kennedy assassination, at least ninety percent of which are works supporting the view that there was a conspiracy. As a result of this, the Kennedy assassination has been described as "the mother of all conspiracies". The countless individuals and organizations that have been accused of involvement in the Kennedy assassination include the CIA, the Mafia, sitting Vice President Lyndon B. Johnson, Cuban Prime Minister Fidel Castro, the KGB, or even some combination thereof. It is also frequently asserted that the United States federal government intentionally covered up crucial information in the aftermath of the assassination to prevent the conspiracy from being discovered.