Everyone wants to see inside Warren Buffett's head. One of the world's most successful investors, the CEO of Berkshire Hathaway is a rock star among those who check the markets before their breakfast. His annual shareholder letters are famous, generating the kind of hoopla among his followers as a just-released Harry Potter novel does among children. Even U.S. President Barack Obama listens to Buffett, or at least he quotes him often. In fact, headline writers have come to call Buffett the 'Oracle of Obama', a play on the Nebraska native's nickname of the 'Oracle of Omaha'.