The Computer Connection by Alfred Bester

Alfred Bester's first science fiction novel since The Stars My Destination was a major event--a fast-moving adventure story set in Earth's future. A band of immortals--as charming a bunch of eccentrics as you'll ever come across--recruit a new member, the brilliant Cherokee physicist Sequoya Guess. Dr. Guess, with the group's help, gains control of Extro, the super-computer that controls all mechanical activity on Earth. The plan to rid Earth of political repression and to further Guess's researches--which may lead to a great leap in human evolution to produce a race of supermen. But Extro takes over Guess instead of turns malevolent. The task of the merry band suddenly becomes a fight in deadly earnest for the future of Earth.Sequoya Guess, whom they love, must be killed. And how do you kill an immortal?