Cut Yourself from the Herd.(price-earnings ratio )(trends of budget deficits )(Brief article)

Byline: ROBERT FRICK

The questions in Ken Fisher's new book, The Only Three Questions That Count (John Wiley & Sons, $28), seem cryptic. They boil down to: What do you think you know that you don't know? What can you know that others can't know? And, in a bow to the relatively new field of behavioral finance, what is your brain doing to trip you up?

Fisher, a money manager and Forbes columnist, says that answering those questions can free you from the tyranny of market myths. Among them: that a market that sells at a high price-earnings ratio is riskier tha