A New York Times survey:
In his 1988 novel, Don DeLillo weaves together fact and literary invention to create a fictional biography of Oswald. The would-be assassin is not unlike many angry young men of literature: misunderstood, antisocial and emotionally isolated. He becomes a pawn in a plot by ex-C.I.A. operatives to provoke war with Cuba by trying to kill Kennedy.
Source: In Movies, Books and TV, a Rabbit Hole of Kennedy Conspiracies – The New York Times