Andre Norton: Secret of the Lost Race. This originally appeared as half of an Ace-Double in 1959.

Joktar didn't know who he was or where he came from. He'd been an orphan in the spaceman's helltown of interstellar N'Yok all his life - adept at dodging the law, outwitting the criminal. He knew of no special reason all the forces of the civilized galaxy should suddenly concentrate on him. Joktar ran for his life, across the stars to the Constellation of the Wolf, and laired on the ice-world of Fenris, waiting for his hunters. Until he learned there was Something Else - something even more feared - out there among the myriad stars that was looking for him… with a chance of life instead of death as its purpose.