Mostly Harmless

Mostly Harmless is the fifth book in Douglas Adams's Hitchhiker's Guide series and the last one published in his lifetime. After losing Fenchurch during a hyperspace jump gone wrong, Arthur Dent drifts through the galaxy trading commodified pieces of himself for passage, eventually settling on the remote planet Lamuella to make sandwiches for its inhabitants. His path crosses again with Trillian and a headstrong teenage girl named Random, while — on a very different version of Earth — journalist Tricia McMillan finds herself entangled with an alien species that has quietly taken up residence nearby.

Darker and more melancholic than the four books before it, Mostly Harmless trades some of the earlier books' antic energy for a more resigned, cosmic irony, closing out the series' central storyline on a notably bleaker note than readers of the earlier volumes might expect.