The Intelligent Investor IMO is one of the best books I have ever read on investing and understanding the market in general.
Yes, though it's a bit archaic. The chapter describing Mr. Market is a must-read.
I posted about Mr. Market after reading several posts from apparently newbie investors worried about short term drops in their 401(k)s.
Maybe we need to break out the hamburger metaphor:
“To refer to a personal taste of mine, I’m going to buy hamburgers the rest of my life. When hamburgers go down in price, we sing the ‘Hallelujah Chorus’ in the Buffett household. When hamburgers go up in price, we weep. For most people, it’s the same with everything in life they will be buying — except stocks. When stocks go down and you can get more for your money, people don’t like them anymore.” - Warren Buffett.