It's worth occasionally reminding people -- particularly media types angry that some guy named "Atrios" is a major force in commentary despite lacking any of those unnamed credentials Real journalists have -- that Duncan Black actually possesses an economics PhD, and used to be a professor at the University of California at Irvine and Bryn Mawr. And in case you need another reminder, his capsule description of how the housing bubble arose is very clear, and very helpful, and quite a bit better than anything I've read in the papers.
