From the back cover of the Ace first edition: "Escape in hell... The Omega Cage. A hi-tech prison on a isolated planet. Dumping ground for the scum of the galaxy - and special enemies of the brutal Confed. They said escape was impossible. If Warden Stark and his merciless hunting machines didn't get you, the bone-littered desert and deadly swamps would claim anyone unlucky enough to survive. Now, Dain Maro, sentenced to the Omega Cage for a crime he didn't commit, is about to attempt the impossible..."
Source · ISFDB CC BY 4.0
