Alan Greenspan, chairman of the Federal Reserve Board, has been called the most powerful man in America, after President Clinton. As head of the nation's influential central bank, Greenspan and the Fed have played a key role in the nation's nearly 10-year record of uninterrupted economic growth. The Fed effectively sets the interest rates that banks charge for loans, which in turn affects the inflation rate. Defenders of the Fed say that by acting aggressively to cool down America's booming economy, Greenspan has kept inflation in check and the expansion going. But critics say the rate hikes were an overreaction that will unnecessarily dampen economic growth. Other analysts say the Fed has too much power and that its deliberations should be more open to the public.