Identity Theft

Identity Theft is a hard-boiled detective novella set on Mars, written by the man Anne McCaffrey calls "an absolutely marvelous writer."
Cassandra and Joshua Wilkins are fossil hunters who have both recently transferred their minds into artificial bodies, but now Joshua has mysteriously disappeared. Cassandra must hire Alex Lomax, the only private detective on the Red Planet, to locate Joshua before sinister forces get to him.
The novella Identity Theft is a nominee for both the Nebula Award and Hugo Award and has been optioned for film.