Mostly Harmless is a novel by Douglas Adams and the fifth book in the Hitchhiker's Guide to the Galaxy series. It is described on the cover of the first editions as "The fifth book in the increasingly inaccurately named Hitchhikers Trilogy".
The title derives from a joke early in the series, when Arthur Dent discovers that the entry for Earth in The Hitchhiker's Guide to the Galaxy consists, in its entirety, of the word "Harmless." His friend Ford Prefect, a contributor to the Guide, assures him that the next edition will contain the article on Earth that Ford has spent the last 15 years researching—somewhat cut due to space restrictions, but still an improvement. The revised article, he eventually admits, will simply read "Mostly harmless." It later turns out that Ford had written a long essay on how to have fun on Earth, but the editors in the guide's main office building edited everything out. Later in the series, Ford is surprised to discover that all of his contribution had been edited back into the Guide (which makes no sense for a seemingly demolished planet) prompting his reunion with Arthur on the alternative Earth in So Long, and Thanks for All the Fish.
After the events in So Long, and Thanks for All the Fish, Arthur Dent and his love interest Fenchurch attempt to sightsee across the Galaxy, but when Fenchurch disappears during a hyperspace jump due to being from an unstable sector of the Galaxy, Arthur becomes depressed and travels the Galaxy alone, raising money to pay his passage by donating his biological material to DNA banks. He is aware that he cannot die until he visits Stavromula Beta, as was revealed in Life, the Universe and Everything, by the insane Agrajag. During one journey, his ship crash lands on the planet Lamuella; Arthur survives and finds a simple life, becoming the sandwich maker for the local population.
Meanwhile, Ford Prefect has returned to the offices of the Hitchhikers' Guide, and is annoyed to find out the original publishing company, Megadodo Publications, has been taken over by Infinidim Enterprises. Ford discovers that Vogons are part of the Guide's employ, and attempts to escape the building. During this attempt, he finds the Hitchhiker's Guide Mk. II, which he steals and sends to Arthur for safekeeping. Arthur, as Ford had expected, stores the package away without even opening it and forgets about it.
One day, Trillian arrives on Lamuella, and presents Arthur with Random Dent, a teenage girl she claims is his daughter, conceived by Trillian via artificial insemination using the only human sperm samples available, those given by Arthur to pay for his space travels. Trillian leaves Random with Arthur so that she can better pursue her new career as an intergalactic reporter. Random finds life on Lamuella boring and cannot get along with Arthur, and comes across the Guide Mk. II. With Random as its owner, the Guide helps her to escape the planet to find her mother. Ford appears shortly after, looking for the Guide. Together, Ford and Arthur manage to leave the planet and return to Earth, realizing that Random has also returned there. Ford also realizes that the Guide Mk. II, being capable of both time-travel and looking into alternate universes, is manipulating events in accordance with an unknown plan.
Full article ▸