Michael Hall conducted important work in applied and computational mathematics with especial reference to aeronautical engineering. He made significant research contributions in the study of unsteady and three-dimensional boundary layers, in vortex dynamics including vortex breakdown, and in the computation of nonlinear inviscid transonic flows. His later work was on Navier-Stokes solvers, including turbulent models. Since the 1970s, the field of computational fluid dynamics has been developed very strongly, including important advances in the computation of inviscid transonic flows. Michael was in the forefront of this activity and his multigrid Euler equation solver is thought to be one of the very best available. As one of the leaders in computational fluid dynamics, Michael showed also a keen appreciation of the practical consequences for aeronautical design of results obtained by numerical computation. In 1991 Michael founded his consultancy Hall C.F.D. Limited which he carried through until 2003.