This is the story of The Hitchhiker's Guide to the Galaxy, perhaps the most remarkable, certainly the most successful book ever to come out of the great publishing corporations of Ursa Minor. . . . It has the words "DON'T PANIC" inscribed in large, friendly letters on the cover.

This line appears near the opening of Douglas Adams’s comic science-fiction novel The Hitchhiker’s Guide to the Galaxy (1979), adapted from his earlier BBC radio series (first broadcast 1978). Adams introduces the fictional in-universe reference book, “The Guide,” with mock-encyclopedic grandeur, treating it as a mass-market product of “the great publishing corporations of Ursa Minor.” The phrase “DON’T PANIC” becomes the Guide’s defining slogan and a recurring motif across the series, encapsulating Adams’s blend of cosmic scale, bureaucratic satire, and deadpan reassurance in the face of absurd, often catastrophic events.

The passage satirizes both publishing hype and humanity’s desire for authoritative manuals. By calling the Guide “perhaps the most remarkable, certainly the most successful” book, Adams parodies promotional language while also establishing the Guide as a cultural artifact within the story’s universe. “DON’T PANIC,” rendered as a friendly cover inscription, functions as comedic understatement: in a universe of incomprehensible dangers and indifferent systems, calm is less a rational conclusion than a survival posture. The slogan also signals the series’ ethos—treat existential dread and modern bureaucracy with humor, skepticism, and a refusal to be overawed.