Did Douglas Adams write the series?
Or did he just pick up the ball and run with it?
Yes, the radio series (at least the 1st 6 episodes) came 1st, and were written by Adams.
I’m not sure if the next 6 episodes came before of after the 1st book.
Brian
The radio series was the first, and it’s well worth checking out if you haven’t heard it. Lots and lots of funny stuff that never made it into the books.
(happy dance)
I just picked up an MP3 CD with the whole series!
Sorry to sound snarky (but I will anyway), but it’s not like information about the Hitchhiker’s Guide to the Galaxy is hard to find on the 'net.
IIRC, it was radio first (often with pages written just before recording time).
Then the books, cobbled with bits rearranged from the radio scripts.
Then the TV series, with the lovely British tradition of low-budget sci-fi.
Then the Infocom computer game.
Then the other two novels.
And (at long last) the movie.
You can also throw in the musicals and the “new” radio shows in there somewhere…
The current printings of the compilation of the five books begins with a foreword by Adams that details the history of the stories and the various formats (books, radio, etc.) you may want to check that out.