When I ran across the Vintage Science Fiction not-a-challenge at The Little Red Reviewer, I thought it would give me a perfect excuse to re-read one of those early favorites that made me fall in love with science fiction.
The Zero Stone is a 1968 novel by Andre Norton. It can be read online here. Norton was one of the first sff authors I discovered, and I read several of her works early on. I'm not sure why I quit reading her books as I got older, but it may have been because I wanted to keep trying new authors and just never got back around to her. She's one of the authors responsible for my continuing love of the genre, and I think of her fondly. I was sad when she died in 2005 at age 93.
from the back of the book:
A mysterious stone, born of worlds long extinct, is the key to powers unimaginable to man —powers that could enable its owners to control the universe. Murdoc Jern, gem trader, finds that possession of the stone has led him to the center of a web of intrigue and murder.The SF Reader gives the book a positive review and says, "The relationship with Eet is the strength of this book." Kirkus Reviews likes the "Good sustaining action".
With his companion Eet, an inscrutable feline mutant with phenomenal ESP powers, he is hunted through space, coming finally to a long forgotten planet inhabited by apelike "sniffers." There, facing the predatory sniffers, the antagonistic Patrol and the laser-guns of the Thieves' Guild, Murdoc must seek the source of the Zero Stone and bargain for his right to pursue his destiny as a free man.