The Hitchhiker's Guide to the Galaxy
The funniest book the genre has produced and one of the most beloved British novels of any kind — radio, TV, film, towel and the name of at least one asteroid attest to a cultural footprint few authors match.
Series Guide
The Hitchhiker's Guide to the Galaxy
Adams's increasingly inaccurately named trilogy in five parts: Arthur Dent, Ford Prefect, one towel, and a universe that is not merely stranger than imagined but actively taking the mickey.
In the Guide
The Restaurant at the End of the Universe
Generally rated the sharpest of the sequels, with the B Ark as perhaps the most pointed satirical conceit in comic SF.