[Haskell-cafe] Who started 42, and when?

I have read quite a lot of Haskell papers, lately, and noticed that the number 42 appeared quite often, in informal tutorials as well as in very serious research papers. No wonder Haskell is the Answer to The Great Question of Life, The Universe, and Everything, but I would like to know who started this, and when. Google wasn't much help, and I can't believe it's coincidence --hence this email. I hope I didn't opened some Pandora box. :-) Cheers, Loup