Ace Double back-to-back paperback, 1970 1st edition. Along with "A Feast Unknown" these are part of Farmer's Grandrith/Caliban series involving characters meant to mirror Tarzan and Doc Savage.
Ace Books, 1980. Reprints the back-to-back Ace Double from 1970. Along with "A Feast Unknown" these are part of Farmer's Grandrith/Caliban series involving characters meant to mirror Tarzan and Doc Savage.