"SuperSnowDragon" was kind enough to create a FAQ document for Klondike Solitaire. Here's an excerpt:
I am so glad you asked that question! It is a card game designed to be played by one person. It is a great way to take your mind off the drudgery of the real world and not become a Cubicle Zombie (though you may turn into a Solitaire Junkie if you do not moderate your playing time). It is a cover-up for things you may be doing that you do not want other people to see! You may cover it up with things that you may be doing because you don't want other people to see you playing Solitaire! (You see, it works both ways.)
Seriously, if you want to know how to play Solitaire, see that all-encompassing section entitled "How Does One Go About Playing Solitaire?"
If you want to know what's up with Solitaire and why it's such a big thing today, read "A Brief History of Solitaire", immediately following this section.
If you want to know how to cheat your way through what may be the world's simplest card game ever conceived, see "How to Cheat at Solitaire." There are easy-to-follow instructions on how to play Solitaire like a bad person.
And even though Solitaire is a card game designed to be played by one person, it is also all of the other things that I said in that needlessly lengthy paragraph above this one. Let's move on!
Lots of great information here!