Couple of lessons Herb Greenberg of Market Watch passes on. First numbers don't lie. Second Quality of earning is important not just the quantity. The real story he says quoting Thornton Oglove is on the balance sheet, and on the cash flow statement. Third GAAP does not mean that much things can go lousy even with GAAP. Fourth do not confuse stock and companies, they can go in opposite directions. Just because a stock is going up does not mean anything, is it just momentum or is it because its artificially pushed up by investors by a rotation from one industry group to another because a certain sector happens to be in favor. Momentum he says can take you to infinity and beyond but you can wind up learning momentum's dark side : reverse momentum which tends to kick in when least expected. And fifth very important in the Buffett tradition that rules No. 1, 2 and 3 are all the same: don't lose money. When making an investment ask not how much you can make but how much can you lose? A parting column from someone who has been around the world of stocks and his mentor of sorts Thornton Oglove....