Happy Birthday Alice

Happy Birthday Alice! – 159 years an inspiration on this earth or under it today. LCSNA member Bob Mitchell has sent us this birthday musing:
Let me ask the two of you a curious question: Lewis Carroll was born in 1832 and Alice was born in 1852. Since 1842 is exactly half way between those two numbers did that peak his interest in the #42? The question was caused by an extremely odd dream I had a few weeks ago.
Most excitingly, this is the very first non-spam response to the question I posed back in October 2010: Why were both Lewis Carroll and Douglas Adams so interested in the number 42? As a non-mathematician it seems to me quite random. Let me mark the occasion of Alice’s birthday by reopening the question: What is so cool about the number 42? Explanations drawn from mathematical theory, literary studies or odd dreams are all welcome (particularly the latter). May the 4th be with you.