Ex-agent: I almost shot LBJ hours after JFK murder

In "The Kennedy Detail," Gerald Blaine recalls standing guard outside the Washington home of newly sworn-in President Johnson in the early hours of November 23, 1963.

Blaine heard footsteps approaching. He picked up his submachine gun and, in the darkness, pointed it at the chest of a man who turned out to be Johnson.

Blaine writes that the enormity of what had almost happened left him chilled. He realized that, 14 hours after losing one president, the nation had almost lost another one by his hand.

He says his book is the first account of the assassination by a member of Kennedy's security detail.