This Star Shall Abide aka Heritage of the Star

(This book is known in the UK as Heritage of the Star) Noren can see that his world is not as it should be--it is wrong that only the Scholars, and their representatives the Technicians, can use metal tools and Machines. It's wrong that only those few have access to the impenetrable City, which he has always longed to enter. Above all, it is wrong for the Scholars to have sole power over the distribution of knowledge. Unable to believe in the Prophecy that promises these restrictions will someday end, he declares it to be a fraud and defies the High Lew under which they are enforced. His family and the girl to whom he is betrothed reject him. Yet he cannot turn back from the path that leads him to the mysterious fate awaiting heretics.
This classic science fiction novel is enjoyed by readers age 12 and up as well as by teens and adults who go on to read the other two books in the Children of the Star trilogy. Originally published in hardcover by Atheneum in the US and by Gollancz in the UK under the title Heritage of the Star, it was the winner of a Christopher Award given for "affirmation of the highest values of the human spirit."