This is the first book in Douglas Adams's highly successful series. It is a very dry, very witty, satire; it begins on a Thursday in Britain. The protagonist, Arthur Dent, is shaving when he notices trucks moving in, intending to demolish his house for a bypass. While he is busy halting the trucks with his body, his highly distracted friend Ford Prefect appears. Ford has been posing as an out-of-work actor, but he is in fact a roving journalist for a highly remarkable book -- the Hitchhikers Guide to the Galaxy. He comes from a planet near Betelgeuse, and he tells Arthur that the world itself is about to be demolished -- for a hyperspace bypass by Vogons.
The two of them escape, at the very last moment, by hitching a ride on the Vogon ship. Vogons are known for being disgusting and cruel creatures (and some of the worst poets in the known Universe), so when they catch the pair, they are tortured (have poetry read to them) and are thrown off the ship into the vacuum of space. By an amazing coincidence, they are rescued right before they die -- by the spaceship Heart of Gold.
The Heart of Gold spaceship is a new, experimental, model powered by the Infinite Improbability Drive; it was recently stolen by the President of the Galaxy, Zaphod Beeblebrox, and his girlfriend, Trillian.
With the Improbability Drive, it's only logical that Zaphod is Ford's cousin, and Trillian is in fact Tricia McMillian, an Earth girl Arthur had met at a party and totally failed to hit it off with. They are using the ship to get to the lost planet of Magrathea, which was once a highly successful commercial venture -- they made speciality planets for the fantastically wealthy. At the moment, it is asleep -- and the missiles their automated systems launch are merely a 'courtesy detail'.
This book is driven by its characters, its wit, and also deep philosophical questions. It is the story of the quest for the meaning of life -- but it's also light and entertaining. The narration, constantly interrupted to provide bits of colour about galactic society, resembles that of the original radio play. The dialogue is witty, very dry humour; the sections from the 'Guide' which Adams quotes within the novel itself are hilarious.