"The Heaven Makers" by Frank Herbert
"The Heaven Makers" first appeared in novel form in 1968, though it was serialized a year before that. This would put it several years after "Dune", for which Frank Herbert won the Nebula award.
The plot concerns an alien race which manipulates human history for the sake of entertainment. This alien race, the Chem, are immortal and virtually indestructible. About halfway through the novel, a human woman is abducted by the Chem for their sexual amusement, and her lover, a psychologist, becomes aware of how the Chem have manipulated events within their small town.
And I'll agree that it sounds like the basis for a good novel, but most of the book is taken up with courtroom drama, and the way in which the "hero" overcomes the alien at the end is both contrived and ridiculous. Even aside from these points, "The Heaven Makers" is simply boring. The characters are uninteresting, and their actions don't make a lot of sense.