James Binney showed that Zeldovich’s pancake model of galaxy formation would lead to elliptical galaxies that were not flattened by rotation, a prediction subsequently confirmed by observation. He has been a distinguished developer of new computer-based methods for studying the internal dynamics of galaxies. He was among the first to argue that active galactic nuclei prevent plasma in so-called ‘cooling flows’ from cooling, and then first to point out that this explained the absence of very luminous galaxies. James and Scott Tremaine wrote the standard reference work on galactic dynamics. He has used results from the Hipparcos satellite and subsequent ground-based surveys to build more accurate models of the galaxy.