"Killing Reagan" is a book by Bill O'Reilly and Martin Dugard that explores the events surrounding the assassination attempt on President Ronald Reagan in 1981. The narrative details the motivations of the shooter, John Hinckley Jr., and the impact of the attack on Reagan's presidency and personal life. The book also examines the political climate of the time, including the challenges Reagan faced in his early presidency. It highlights how the assassination attempt shaped public perception of Reagan and influenced his policies moving forward, ultimately contributing to his legacy in American history.