Central banking is being turned upside down by innovations such as securitization, complex options dealings and Euro-asset transactions that are denationalizing money and making it impossible for central banks to regulate costs of capital. Nor can central banks modulate business cycles in open economies; study of banking policy and business fluctuations suggests that the ''real'' importance of bank-credit changes has long been exaggerated. The new art of central banking may culminate in masterly inactivity.