Edit: Okay, to be honest, I don't know what this is. Would you care to explain, NNescio?
"What's 42?"
"The answer to the Ultimate Question of Life, the Universe, and Everything."
“Forty-two!" (yelled Loonquawl) "Is that all you've got to show for seven and a half million years' work?"
"I checked it very thoroughly," (said the computer,) "and that quite definitely is the answer.
As for this part:
では42という数字にはどんな意味が込められているのだろうか?
SFファンの間では様々な推測や仮説がなされてきた。
しかし作者ダグラス自身は42の意味についてこう答えている。
「意味なんてない。ただのジョークだよ」
42という数字自体には、何の意味もないのだ。
ディープ・ソートが言っているように「究極の疑問」すらも、私たちは理解できないのだから。
So what exactly is the meaning behind the number 42?
Plenty of theories were put forth among science fiction fans.
But the Author himself, Douglas Adams gave this answer on the matter of the meaning behind 42:
"There's no deep meaning behind it. It was just a joke"
(Actual quote: "The answer to this is very simple. It was a joke. It had to be a number, an ordinary, smallish number, and I chose that one. Binary representations, base thirteen, Tibetan monks are all complete nonsense. I sat at my desk, stared into the garden and thought '42 will do' I typed it out. End of story.")
So the truth behind the number 42 is, well, that it has no meaning at all.
Because, well, we wouldn't be able to understand the Ultimate Question even if Deep Thought itself tells us.