John B. Bell is an American mathematician and the Chief Scientist of the Computational Research Division at the Lawrence Berkeley National Laboratory. He has made contributions in the areas of finite difference methods, numerical methods for low Mach number flows, adaptive mesh refinement, interface tracking and parallel computing. He has also worked on the application of these numerical methods to problems from a broad range of fields, including combustion, shock physics, seismology, flow in porous media and astrophysics.