The Ganymede Takeover is a 1967 science fiction novel by American writers Philip K. Dick and Ray Nelson. It is an alien invasion novel, and similar to Dick's earlier solo novel The Game-Players of Titan. Dick later admitted that The Ganymede Takeover was originally going to be a sequel to his alternate history novel The Man in the High Castle with the Japanese occupying the United States not Ganymede.

Earth has been taken over by a strange alien force - creatures whose instinct for survival overrides any human resistance.
Then a vital weapon - with the powre of electronically warping the mind - falls into the hands of a terrorist group still strong enough to oppose the aliens. A weapon so powerful that it cannot be controlled.
The control of Earth is in the balance - and the balance is a terrifyingly precarious one.