This is a great game but not many people know that The Hitchhikers Guide to The Galaxy is also a book.
1. All of the books made it to the bestseller lists
2. The radio series on BBC was a cultural phenomenon
3. Douglas Adams is the canonical author for "can anyone write an SF comedy which is funny?"
Well, for a start, the hilarious _Good Omens: the Nice and Accurate Prophecies of Agnes Nutter, witch._ Co-written with Terry Pratchett, also a great radio serial and a wonderful TV series from about 3 years ago.
Secondly, multiple superb novels, such as _Stardust_ and _Coraline_, both adapted into successful feature films; _Neverwhere_, a low-budget British TV series; and _American Gods_, a huge, big-budget TV series.
Everything he has written has a rich vein of humour. Even perhaps the most tragic of the Sandman series, _Death: The Sound of her Wings_.
"You keep doing that, you know what you're going to get? "FAT PIGEONS!"
This is more a matter of general cultural awareness, I would say. Gaiman's writing career goes back to _Don't Panic_, a book _about_ the Hitchhiker's Guide some 30 years ago now. He is a lot more than just a comics writer.
Anyway. I hope you try some of the books and enjoy them. I would say that he is perhaps more of a fabulist than a novelist -- a lot of his novels to me strike me as being akin to fairy tales, myths or legends, but with a fine modern sensibility.
I would probably suggest reading it before watching the series, if you were so inclined -- it's very good indeed, but strongly aimed at the readers of the book. It's a bit wordy in places.
The radio adaptation was also excellent: https://www.bbc.co.uk/programmes/b04knt4h
It has cameos by both Gaiman and Pratchett. A sample from Youtube: https://www.youtube.com/watch?v=S_LMCx9nfAk
Some samples...
“There are some dogs which, when you meet them, remind you that, despite thousands of years of man-made evolution, every dog is still only two meals away from being a wolf. These dogs advance deliberately, purposefully, the wilderness made flesh, their teeth yellow, their breath a-stink, while in the distance their owners witter, "He's an old soppy really, just poke him if he's a nuisance," and in the green of their eyes the red campfires of the Pleistocene gleam and flicker.”
“She was convinced that she was anorexic, because every time she looked in the mirror she did indeed see a fat person.”
“God does not play dice with the universe; He plays an ineffable game of His own devising, which might be compared, from the perspective of any of the other players [i.e. everybody], to being involved in an obscure and complex variant of poker in a pitch-dark room, with blank cards, for infinite stakes, with a Dealer who won't tell you the rules, and who smiles all the time.”