The worm-kings of Ganymede had not suspected there was other intelligent life in the solar system until a space probe bounced down on their surface. But that was enough to whet those super-beings' appetites for conquest. After their takeover of the Earth, however, it turned out that these unruly Earth people presented a number of unpredictable problems. And they soon learned that their primary troubles were coming from such a mixed bag as Percy Y, a fanatic guerrilla leader, Dr. Balkani, an anti-social scientist, Joan Hiashi, a psychedelic folk singer, and a mysterious television personality nobody could get their hands on at all. THE GANYMEDE TAKEOVER is an idea-apage action novel up to the best standards of Philip K. Dick.

From the back cover of the 1977 Ace edition

In their lust for power, the worm-kings of Ganymede had conquered Earth... now they had to rule it. But the superbeings found that they had to regulate an unusually troublesome and unpredictable planet. How could such an inferior people create so many problems? How could a race be so unteasonable? And how would the victors hold what they had won? ..

I regard Philip Dick as a major novelist.... In the next decade or so, Phil's multiplex view of the world-his ability to see and deal with five contradictory realities at once-may become a prerequisite to sane survival." -Paul Williams, in ROLLING STONE"