The first of a new series spun off from Stasheff's paperback Warlock yarns (A Wizard in Absentia, 1993, etc.). Like his Warlock father, Rod Gallowglass, Magnus d'Armand has wizardly powers (actually various ESP, telepathic, and telekinetic abilities) and has dedicated himself to overthrowing oppressive totalitarian regimes throughout the galaxy. His secret ally is Herkimer, his intelligent computer-cum-spaceship. On planet Petrarch, the most advanced culture has been frozen at a Renaissance level ever since the revolutionary Earth interstellar government cut off technological aid. Also at work on Petrarch, posing as gypsies, is a team from AEGIS, an Earth-funded organization of misguided reformers whose interference usually causes more harm than good. Magnus, taking the guise of mercenary soldier, befriends Gianni, the son of a merchant from the prosperous island city of Pirogia. Gianni, protected and encouraged by Magnus, persuades the reluctant Pirogia merchants to prepare for war against the arrogant feudal lords of the mainland. The lords, it turns out, are supported not by AEGIS but by the interstellar Lurgan Company, which is making staggering profits exporting Petrarchian gemstones. Ingenuous head-bashing for the most part: a natural mass market title clearly out of its league in hardcover format.