Mostly Harmless

Mostly Harmless came out in 1992, and it was the fifth book in the Hitchhiker's Guide series as well as the last of them that Douglas Adams wrote; it was also the last of his books to appear in his lifetime. The first edition's cover described it, in the series' own style, as the fifth book in an increasingly inaccurately named trilogy.

Arthur Dent sets out to travel the galaxy as a sightseer with his girlfriend, Fenchurch, who vanishes during a hyperspace jump because she came from an unstable part of the galaxy. He carries on alone, paying his way by selling samples of his own body, and eventually finds himself stranded on the very ordinary planet Lamuella, where he settles in as the local sandwich maker.

Ford Prefect, meanwhile, comes back to the offices of the Guide and discovers that the original publisher has been taken over by a company run by the Vogons. He leaves in a hurry, taking with him the not-yet-published and apparently sentient Guide Mk. II, and goes into hiding.