Mostly Harmless

The fifth book in the Hitchhiker's Guide to the Galaxy “trilogy” is the novel Mostly Harmless. Written by Douglas Adams and published in 1992, the funny science fiction series follows the adventures of a group of somewhat hapless friends as they make their way across the universe. Guided by an intergalactic travel book, the eponymous “Hitchhiker’s Guide to the Galaxy,” they encounter many of the typical tropes of more serious science fiction, only for each situation to diffuse or resolve itself through humor, confusion, or logical chaos. However, this fifth book is a tonal departure from the four that preceded it, with even Adams himself admitting that his personal life had bled into his work and created “a rather bleak book.”

The previous book in the series ends with the revelation that despite having been destroyed at the very beginning of the story, the planet Earth has been restored by dolphins who simply extracted another version of the planet from somewhere else in the multiverse.

The novel’s title is a joke from earlier in the series. Initially, the Hitchhiker’s Guide entire entry on planet Earth is “Harmless.” However, one the characters spends 15 years expanding this description for the next edition of the Guide – but his detailed, researched article ends up being slightly edited due to space restrictions. The new entry reads: “Mostly harmless.”



Our protagonist remains Arthur Dent, a human who has spent the previous four novels traversing the galaxy, but who ended the fourth book back on Earth. Mostly Harmless jumps forward in time slightly and reveals that Arthur is once again exploring space, funding his adventures by donating his DNA. At first, some of his usual caution is gone, since Arthur believes in a prophecy that he cannot die until he has once again killed an endlessly reincarnating being called Agrajag somewhere called Stavromula Beta – something he has no plan of doing.

But soon, Arthur’s usual depression returns. After he crash-lands on the quiet and peaceful planet Lamuella, where the backward inhabitants worship the Almighty Bob, Arthur decides to build a new life as a master sandwich maker. Soon, his life is disrupted by the arrival of Trillian, a human astrophysicist who at first traveled in space with Arthur, but whose intrepid and daring personality propelled her into the much more exciting life of being a Sub-Etha Radio reporter. Using Arthur’s donated DNA, Trillian gave birth to a daughter. Now, she drops off the teenage Random Dent with her biological father, and leaves to further her career.

Meanwhile, Arthur’s friend Ford Prefect, a writer for the Hitchhiker’s Guide and originally from the planet Betelgeuse 5, finds out that the Guide’s publisher has been bought by Vogons, a nasty alien species who write awful poetry and started the series by destroying Earth to make room for an intergalactic bypass. Ford just barely escapes their clutches, but manages to steal a copy of a new version of the Guide: a sentient Guide Mark II. For safekeeping, he mails this new Guide to Arthur and travels to Lamuella.



Completely bored in Lamuella, Random steals Ford’s package before he can get to it. The Guide Mark II helps her steal Ford’s spaceship and run away in search of her deadbeat mom. Ford and Arthur manage to find another ship, and make for Earth, which is where they suspect Random is headed.

In the meantime, Trillian, who has been covering an ongoing war, realizes that because of a time anomaly, one of the Grebulon warships has appeared in Earth’s space. Having lost most of their memories, the Grebulons spend their time watching Earth TV and demand that Trillian read their horoscope. Because Earth is in the way, the horoscope comes out unfavorable. Seeing that the Grebulons are willing to destroy Earth to get a better horoscope reading, Trillian heads to Earth to warn its people.

On this version of Earth is an alternate-universe Trillian, Tricia McMillan, who didn’t end up going to space with the two-headed Zaphod Beelebrox, but who did become a reporter. After hearing reports of a spaceship landing in the middle of London, Tricia goes to investigate only to encounter an enraged Random leaving the ship. Thinking that Tricia is actually her mother Trillian, Random explodes about the variety of ways she feels abandoned. Just then, Arthur, Ford, and Trillian arrive. Seeing two versions of her mother, Random freaks out and has a near psychotic break.



The group finds its way into a nearby bar and try to calm Random down. At the same time, Trillian is desperately insisting that everyone needs to immediately get off planet because the Grebulons are going to destroy it at any second – although Arthur doubts this could happen since he still hasn’t ever killed Agrajag on Stavromula Beta. Fed up with the chaos, Random brandishes a laser gun she took from Ford’s ship and distractedly fires it. The blast hits a man leaving the restroom. As Arthur tends to the man’s wounds, the man blames him for his coming death and reveals himself to be yet another incarnation of Agrajag. It turns out that the bar is the Greek owner’s second attempt to build a small business – it’s called “Stavros Muller’s Beta.”

Just in that second, the Grebulons fire on Earth and destroy it. Arthur dies with a feeling of tremendous peace at the fact that the loop of his life has been closed. Ford dies laughing wildly at the ridiculous coincidences.

It is then revealed that the Guide Mark II is actually a creation of the Vogons, who designed it to be able to see the possible outcomes of any event and thus enable the Vogons to destroy all possible versions of the Earth once and for all in all universes, times, and realities. Now that this has been accomplished, the Guide implodes.



The Grebulons redo their horoscope now that Earth is out of the way, but still the result is unfavorable. The novel ends with the Grebulon captain mildly annoyed that now there’s nothing to watch on TV.

After the novel’s publication, Adams expressed dissatisfaction with this ending as both too depressing and not in line with the cynical, but still upbeat, rest of the series. He intended to write a sixth book, which was completed after his death by Eoin Colfer. Titled And Another Thing…, the sixth novel retcons the ending of Mostly Harmless by having President of the Galaxy and wanted felon Zaphod Beeblebrox rescue the main characters just before the Earth is destroyed.