The Hitchhiker's Guide to the Galaxy is a fictional information source, as seen in a series of very-real novels/radio programmes/TV programmes/movie/computer games/towel/etc.
The Hitchhiker's Guide to the Galaxy is an electronic guide to just about everything, intended particularly for galactic hitchhikers, appearing in the novel (etc.) series of the same name. Its nature should be self-explanatory. If not, go read the novels. It outsells the Encyclopaedia Galactica by virtue of being cheaper, a great deal more portable, and having the words "Don't Panic!" emblazoned – in large, friendly letters – on its cover.
Marvellously, its appearance in fiction (see below) prefigured tablet computers by about 30 years, not to mention it is in many respects analogous to – though again a couple of decades ahead of – the likes of Wikipedia and its own online equivalent, h2g2.
The Guide has been mentioned a few times in fiction from Atlantean Publishing:
Novel series (and multi-media phenomenon: see above) by Douglas Adams. Generally regarded as 'quite good'. Mentions Southend-on-Sea, which is always a bonus. Although not part of the Doctor Who universe as such, Adams' connection to the series and the fact that he reused ideas of his from the show and from rejected scripts make them a perfect, if not always serious, fit. The series includes several people and places that have been mentioned in Doctor Who fan fiction, including:
- The eponymous Guide (above)
- The Encyclopaedia Galactica
- The Restaurant at the End of the Universe
- The Krikkit Wars
- Oolon Colluphid
- mentioned in Once Under Seven Moons... (as Oolan Caluphid)