Does anyone know why 42?

Check out Peter Gill's new book, '42: Douglas Adams’ Amazingly Accurate Answer to Life, the Universe and Everything'. Published on 4th February 2011 by Beautiful Books. B-format paperback. £8.99.

I don't know, but I came across this on Youtube and it sounds like a joke Adams would come up with.
Dice has 6 sides: 6 + 5 + 4 + 3 +2 +1 = 21.
2 x 21 = 42
The answer is two dice. Two dice. To die. The answer to Life, Universe and Everything is to die. XD

Stil, this is just a funny idea and there is a lot of them out there, nobody but Stephen Fry knows for sure. :(

If I might humbly (or, er, not so humbly) suggest my book *Philosophy and The Hitchhiker's Guide to the Galaxy*, published by Palgrave Macmillan . .