The Singers of Time

By Frederik Pohl and Jack Williamson

Earth has been conquered by Turtles, alien beings who are not really turtles but who bear a superficial resemblance to them. The Turtles are a peaceful race and conquered simply through commerce. They love to buy and sell. They made humanity an offer we couldn't refuse and we sold them all our weapons and let them establish a benevolent dictatorship. In their eyes we were backward, slightly intelligent animals.
To the Turtles, physics was a sort of religion, laid down by the Mother turtle, of which there is only one. Like a queen bee, only Mother lays the eggs of each new generation, with several female handmaidens that can step in if the Mother dies. The Mother lives on the Turtle home planet and her word is law. And she has declared that quantum physics is superstition and untrue. As a result, back on Earth, people have stopped trying to expand their understanding of physics and simply go along with the Turtles' view of the universe. Basically, Turtle interference has caused human learning and creativity to stagnate. People no longer have to learn anything, they just insert a Turtle disc into a slot in their brains and instantly know everything they need to. Problem is, when the disc is removed, all memory of that knowledge goes with it.
But then the unthinkable happens. The Turtle homeworld has been devoured by a wormhole or a black hole, things that the Turtles deny can even exist. The Mother is destroyed along with all her handmaidens and the Turtles are doomed to fade away with no ability to reproduce. So two brave Turtles and four young humans and a Taur, an intelligent, cow-like being, set forth for the Turtles home world on a hopeless mission to rescue or restore the Mother and in the process the Turtles are going to learn that there is more than one way to skin a cat, so to speak.

This was a good book. The Turtles are really alien and different and even though they have been inflexible in the past, turn out to be willing to learn from their mistakes. The little group of aliens and humans go forth on a classic science fiction adventure, encounter strange new beings and situations and eventually manage to work together for the benefit of both Turtles and humans. It was an exciting and interesting story although there was quite a bit of physics in it, with snippets of physics lectures included. I just skimmed those parts, not being interested in physics myself. But other than the physics lectures, I enjoyed the story a lot.