Star Hunter. by Andre Norton

On the unexplored jungle world of Jumala, former pilot turned safari guide Ras Hume schemes to collect the reward for finding a missing heir to a fortune. A busboy from local dive bar is brainwashed into believing he is the missing heir, but he soon begins to doubt his own memories. This standalone story was originally published in 1961 as part of a double title paperback by Ace Books along with an abridged version of The Beast Master, and again in 1968 paired with the short novel Voodoo Planet, all by Andre Norton.