A Wizard in Chaos — Christopher Stasheff

The Rogue Wizard

Under the nom de guerre of Gar Pike, renegade psychic wizard Magnus D'Armand travels the stars fighting injustice and oppression, like his father, Rod Gallowglass, the Warlock in Spite of Himself. But unlike his famous father, Magnus refuses to play by the rules, sowing the seeds of freedom and revolution throughout the galaxy.

The Rogue Wizard has met his match--a crumbled civilization on a distant colony planet, where all hope has been lost to war and greed. The history and knowledge of the colonists has been forgotten over the centuries, and the people have reverted to a medieval state. It seems impossible to restore peace and order--until Gar discovers the hidden knowledge harbored in the countryside's hollow hills.