Star Hunter - Andre Norton

"Somewheres on the jungle world of Jumala, there was a man in hiding—a man whose mind had been reconditioned with another's brain pattern and for whom there was a fabulous reward. Star Hunter is a thrill-packed account of that other-worldly game of hide-and-seek between a man who did not know all his own powers and an interstellar safari that sought something no man had a right to find...." (summary from gutenberg etext)