The marvellous thing about picking an old book off the shelf is that when you track it down, its neighbour says, 'Me too!' So it was that today I started leafing through Paul Krugman's 1996 book The Self-Organizing Economy. I'd forgotten what a superb introduction it is to the application of the non-linear dynamics of emergent order. The book applies the concept of self-organizing systems to urban economies and to business cycles, delivered with his usual clarity.

Having read this when it was published, and Thomas Schelling's Micromotives and Macrobehavior, and Paul Ormerod's 1998 Butterfly Economics, and  Barabasi's (2002) Linked on network theory, the more recent and fashionable literature borrowing from similar models in evolutionary biology and physics have all seemed pretty familiar.

Most economists I know are intrigued and excited about these related non-linear models, but remain unsure about their practical utility, so what's actually needed now are some more applications to actual economic phenomena. Here, though, is one online demonstration of Schelling's segregation model, which is as real life as can be.