From the world-famous inventor of fractal geometry, a revolutionary new theory that turns on its head our understanding of how markets work. Fractal geometry is the mathematics of roughness: how to reduce the outline of a jagged leaf, a rocky coastline or static in a computer connection to a few simple mathematical properties - to make the complex simple. With his fractal tools, Benoit Mandelbrot has got to the bottom of how financial markets really work. He finds they have a shifting sense of time, a unique dimension and a wild kind of behaviour that makes them volatile, dangerous - and also beautiful. In Mandelbrot's fractal models, the complex gyrations of IBM's stock price, the FTSE 100, cotton trading and exchange rates can be reduced to straightforward formulae that yield a much more accurate description of the risks involved.