Do you know the Answer to Life, the Universe and Everything?¹
Do you know the Question to the Answer to Life, the Universe and Everything?²
Do you know where your towel is and why that question is important?³
If you know the answer to any of these questions you have Douglas Adams to thank. Douglas, who sadly died in 2001, was born on March 11th in 1952. He is the author of the five book Hitchhiker's Guide to the Galaxy trilogy (Yes, trilogy) as well as the Dirk Gently Holistic Detective Agency novels, a handful of Doctor Who episodes and more.
If you have never read one of his works, pick one up and give him a shot.
²According to some, "What do you get when you multiply six by nine?" (Which actually works in base 13). According to others, it is impossible to know both the answer and the question in the same universe lest the universe destroy itself.
³A towel has immense psychological value. For some reason, if a strag (strag: nonhitchhiker) discovers that a hitchhiker has his towel with him, he will automatically assume that he is also in possession of a toothbrush, washcloth, ...soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet-weather gear, space suit etc., etc. ... What the strag will think is that any man who can hitch the length and breadth of the galaxy, rough it, slum it, struggle against terrible odds, win through, and still knows where his towel is, is clearly a man to be reckoned with.” —The Hitchhiker's Guide to the Galaxy, Chapter 3.