Merlin's Mirror

"In this great science fiction novel, Andre Norton brings to new life the legendary King Arthur and the wizard Merlin in the light of modern knowledge of a lost period of history and today's understanding of science and interplanetary communication. Yet, as in all Norton's wonder novels, this is a fabulous adventure in fantasy. Here is Merlin, half star-born, gifted with the advice of an alien intelligence, given the task of renewing civilization and starting humanity again up the ladder to the stars. Here is Arthur, unaware of his stellar heritage. And here too, is the Lady of the Lake, akin to Merlin in that she is also a listener to the music of the spheres and obedient to a celestial command post."