I have worked in a number of areas, including Complex Analysis, Continuum Mechanics, General Relativity, Numerical Analysis, Quantum Mechanics, Partial Differential Equations and Special Functions. For the past few years I have been principally concerned with systems of hyperbolic partial differential equations, especially those systems which are of particular physical interest--mostly the Einstein equations of General Relativity, but also the Euler equations of Fluid Mechanics and the equations governing Nonlinear Elasticity.

Excellent overviews of General Relativity, in varying levels of detail, are available from Muppet Labs and Living Reviews.