|Methuen paperback, 1976. Cover artist uncredited.|
"Scattered over the densely populated solar system there is a small group of immortals. One of them, Dr Sequoya guess, attempts to take over Extro, the supercomputer complex that controls all mechanical activity on earth. But instead Extro takes over Guess, and the combination turns suddenly evil. Dr Guess must be destroyed - but how do you kill an immortal?"