Andrew Soward is well known for his work on magnetohydrodynamics (MHD) and especially dynamo theory, and also for his significant contributions to linear and nonlinear stability theory. By powerful use of asymptotic analysis, he has solved a number of very difficult problems in applied mathematics. By a new pseudo-Lagrangian technique for studying lightly damped fluid systems, he elucidated previously inexplicable features of Braginskii’s geodynamo. Andrew has also provided explicit examples of steady fast dynamo action, so disproving a conjecture that such dynamos did not exist. Andrew identified new rotating modes of nonlinear convection in rotating systems, and in collaboration with Steven Childress, established a now celebrated MHD dynamo model in a rapidly rotating Benard layer; he also gave the first demonstration that situations exist where oscillatory MHD dynamos generate magnetic fields more readily than steady flows can. Assisted by Eric R. Priest, he provided the first mathematically satisfactory account of the Petschek mechanism of magnetic field line reconnection. Andrew also gave the first complete solution of the Stefan (freezing) problem in cylindrical geometry.