Mostly Harmless

Mostly Harmless is a novel by Douglas Adams, published in 1992, and the fifth book of what Adams himself liked to call a four-part trilogy: The Hitchhiker's Guide to the Galaxy.

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 fifteen years researching, somewhat cut due to space restrictions, but still an improvement. The revised article, Ford eventually admits, will simply read "Mostly harmless." It is a small joke, but Adams chose it for the title of the book that ends everything, and the choice turns out to be pointed: the whole novel is about how very little it takes to undo something that seemed solid.

The story opens with Arthur adrift. Fenchurch, the woman he fell in love with in So Long, and Thanks for All the Fish, has been lost to a hyperspace jump, vanished into an alternate time stream, and a grieving Arthur drifts across the galaxy before settling on the remote planet of Lamuella, where he becomes the village sandwich-maker. It is a quiet, deliberately small life, and one of the few stretches in the series where Arthur is genuinely content. Adams does not let it last. Trillian arrives and hands him a daughter, Random, the result of an earlier and entirely accidental use of a donated sperm sample, and announces she is leaving the girl with him while she covers a war.

Around this sit two other strands. Ford Prefect breaks back into the Guide's offices, now under new and corporate ownership, as an act of rebellion, and steals the Guide Mark II: a sleek, black, bird-like device of unsettling capability that can model every possible version of reality at once. And on a parallel Earth, one that was never destroyed, lives Tricia McMillan, the version of Trillian who declined Zaphod Beeblebrox's invitation to leave at that long-ago party and stayed behind to become a television reporter, quietly haunted by the life she did not take. Adams builds the book around probability and parallel versions of reality, which is the conceit that lets Earth be both destroyed and present at the same time, and lets two versions of the same woman exist in the same plot.

The strands draw together on the reconstituted Earth, where Random, frustrated and increasingly unstable, has fled with the Guide Mark II. What follows is one of the strangest closing sequences in the series. The Grebulons, an amnesiac alien survey crew who pass their time watching Earth television and have come to rely on a horoscope to give their lives shape, find that Earth is spoiling their astrological reading, and decide the simplest solution is to remove the planet. Arthur, meanwhile, believes he cannot die until he has fulfilled an old prophecy about killing Agrajag at a place called Stavromula Beta, and the long-running time loop that has protected him is quietly closed in a nightclub almost by accident. With the loop shut, the protection is gone. The Guide Mark II, it transpires, is a Vogon instrument, engineered to arrange Earth's destruction across every probability at once so that the planet can never again be restored. The book ends, with grim finality, on the deaths of Arthur, Ford, Trillian, Tricia and Random, and the rest of humanity along with them.

It is by some distance the darkest book in the sequence. The absurdist comedy is still present, Ford's break-in, the sandwich-making, the Grebulons and their horoscope, the running gag of Arthur's unwanted fatherhood, but it is laid over a bleakness the earlier books never reached for, and the ending offers no reprieve and no reset button. Adams wrote it during a difficult period and was candid afterwards about the result, attributing the tone to a bad year and acknowledging that readers were right to find the book bleak. He came to regret how grim the ending was. Knowing that adds a layer to the reading: the author was not enjoying himself, and the book does not pretend otherwise.

What gives it weight, though, is that this was the last Hitchhiker's novel Adams completed before he died in 2001, and for a long time it stood as the conclusion of the whole sequence. Whatever one makes of the ending, and opinion has always been divided, this is the book that had to carry the burden of being the end, and it commits to that role completely. The earlier volumes ended with a shrug and an open road; this one closes the door and means it.