Science-fiction comedy-thriller from the ex-Monty Python star and children’s writer. Narrator Bill Reynolds, a professor of evolutionary theory, unearths an old Ph.D dissertation that perceptively examines the wellsprings of comedy—and that was summarily rejected because its author, Carlton, was a robot. Carlton’s ideas are too good to waste, thinks Reynolds, who investigates with larcenous intent. Carlton was the property of a bush-league comic duo, Lewis Ashby and Alex Muscroft, who worked the circuit between Saturn and Mars. Their adventures begin when Lewis and Alex audition for a gig aboard the huge luxury interplanetary liner Princess Diana but, fatally, insult the unspeakably dreadful celebrity Brenda Woolley. With their other gigs suddenly and inexplicably canceled, they decide to head for Mars. At the colony world H9, Alex falls headlong for gorgeous Katy Wallace—but her terrorist associates promptly sabotage H9. While mentally constructing his comedy thesis, Carlton rescues Katy from the imploding planetoid, then saves everyone from a reproducing bomb aboard their own ship. Afterward, stranded and slowly freezing in the cold of space, Carlton experiences a revelation: levity, the opposite of gravity, is the fundamental force that causes the universe to expand—at the speed of laughter! Now he even understands irony. Once thawed out, Carlton must protect his humans from the terrorists who wish their silence. Often delightful, with fair-to-middling thriller elements and a merry yet thoughtful analysis of comedy: should entertain everybody bar the terminally unamused.