This program, and the novel by Adams with the same name published in 1979, featured a fictional electronic reference book containing all knowledge in the galaxy, plus much more. As Adams conceived it, this vast amount of data could be fit into something the size of a large paperback book, with updates received over the "Sub-Etha"—possibly a play on ethernet, which in turn is a play on the concept of the aether. Adams's book and/or the radio series was adapted for television broadcast in January and February 1981 on UK television station BBC Two:
"The Guide is described as resembling 'a small, thin, flexible lap computer' encased in a 'sturdy plastic cover' with the words 'Don't Panic' inscribed on it 'in large, friendly letters'. It is presumably of robust construction, making it able to withstand falling through time/space wormholes and being thrown into swamps, being rescued, and still operating. Arthur Dent's copy survived a spaceship crash which melted the ship into something unrecognizable yet the Guide (and on-board entertainment system) survived. Its entries are arranged alphabetically on the screen and accessed via typing entry codes on a keyboard; 'Earth' is on the same page as 'Eccentrica Gallumbits, the Triple-Breasted Whore of Eroticon 6.'
"In the film  the Guide is depicted as a large metal book with a large screen instead of pages. Entries here are reached by voice activation (e.g. saying the word 'Vogon' will bring up the article on Vogons, etc.) The visual graphics of the guide entries here were animated by Shynola" (Wikipedia article on The Hitchhiker's Guide to the Galaxy (fictonal), accessed 11-08-2013).