Mindswap by Robert Sheckley
The novel “Mindswap” by Robert Sheckley was published for the first time in 1965 in the magazine “Galaxy” as a novella, later expanded into a novel published as a book in 1966.
Marvin Flynn reads a newspaper ad about a Martian willing to participate in a mind-swap with an Earthling. It seems like the perfect opportunity to escape his boring life, so he signs up to participate.
Everything seems to be going as planned, and Marvin Flynn finds himself on Mars, in the body of a native. He doesn’t even have time to adjust to his surroundings before he discovers he’s been the victim of a scammer who used mind-swapping to escape arrest. He’s ordered to return the Martian’s body, but his own body is still in the scammer’s possession, so he must quickly find another body or die.

