Ball, Mankiw, Romer and others style themselves as New Keynesians. Their program is to develop improved microeconomic foundations for imperfectly flexible prices. In the process, they hope to illuminate the paradox that individually rational or near-rational behavior can result in significant collective market failures. These are certainly laudable objectives. In the end, I suspect, the program will not change the essential substance of Keynesian macroeconomics. But it will make Keynes more palatable to theorists.