If memory serves it first appeared as a radio series on BBC Radio 4 in 1978. At the time it was shunted to the dark corners of a 10:30pm nightly slot.
However, word soon got around and very quickly the BBC rebroadcast it at 11:00am on a Sunday morning. It was at this time, as a wee lass, I started to listen to it and got completely hooked.
Soon after that it got turned into a book, then a second radio series, a second book (which differed somewhat from the radio series), a computer game (maddeningly difficult and bore only a small resemblance to either the book or the radio series), a TV series, and a third book.
Some time later, the H2G2 trilogy expanded to 4 then 5 books and is now known as a 'trilogy in 5 parts'. In addition a book of the radio scripts was also published. Also, a web site dedicated to replicating the Guide (albeit with mostly earthbound data only) started up and is now run by the BBC at
The Hitch Hikers Guide Web Site
Tragically, Douglas Adams passed away earlier this year whilst in the process of writing the 6th book of the trilogy. Apparently this book will be published (incomplete) on the anniversary of his death next year.
Books:
The Hitch Hikers Guide to the Galaxy,
The Restaurant at the End of the Universe,
Life, the Universe and Everything,
So Long and Thanks For All the Fish and
Mostly Harmless.
Amazon have excerpts of the first book available to read at
http://www.amazon.com/exec/obidos/tg...32#reader-link
Rachel