Where is Robert Shiller (the bestselling author of Irrational Exuberance) when you need him? In fact, the Yale professor, who accurately foretold the crash of 2001, has just finished tallying the latest Case-Shiller index of top U.S. housing markets, which shows that home prices fell 7.2 percent between December and April, before rising 5 percent between April and August. While historical gaps in data make it tough to track perfectly, Shiller believes we have just seen the sharpest turnaround in American house prices in a century. British and Australian markets are starting to swing up, too, and in many Asian cities, real estate is positively buoyant. How is it possible that home prices are going up again even as employment is going down in most parts of the world, wage growth is nonexistent, and public debt levels are reaching record highs? "We've just gotten very speculative in our behavior, and it's a change that will likely last. I'm inclined to say that we're seeing a new bubble," says Shiller