Jack Williamson 
Mazeway 

From the depths of space the Seeker had come, to make the Solar system her nest. The invader was defeated, but not before the Earth was ravaged, its technology destroyed and its inhabitants reduced to barbarism. Mankind’s only chance for salvation lay with the alien Eldren — but the Eldren considered humanity primitive and savage, and so they withheld their help. Young Benn Dain hoped to prove humanity’s worth on Mazeway, a planetary doublet whose twin worlds, Blade and Stone, were a testing ground for Eldren young. For Roxane Kwan and Diego Bolivar, Mazeway was a path to control of the dying Earth, and Dain’s quest was not part of their plans. But the Game of Blade and Stone was not designed for humans, and to survive, they would have to work together to fathom the depths of alien minds and the subtle traps of Eldren way…