As an answer to "the meaning to life, the universe and everything", this has sparked a great deal of speculation over the years.
Douglas Adams had this to say about it:
"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."