The Wizard of Linn
A. E. van Vogt
 A war between humanity and an extraterrestrial race, known as the Riss had led to the decay of the solar system, and the mutated human genius Clane Linn had defeated the hordes of the barbarian chief Czinczar, as described in the prequel. Linn repudiated Czinczar's exhortation to usurp control of the Linn Empire. After realizing the technological retardation of humanity, he conceives a plan to go on an interstellar expedition in search of technological restoration, to eventually rescue humanity.