This volume is representative of the lectures given at the International Conference on Differential Equations and Mathematical Physics, held at the University of Alabama at Birmingham on March 15-21 1990. It features plenary lectures on topics at the frontier of present day research, focusing on recent developments in the theory of ordinary and partial differential equations, both linear and non-linear, with particular reference to the problems of mathematical physics. Other topics include control theory, scattering theory, and microlocal analysis.