This volume contains the proceedings of a meeting held at Imperial College which is devoted to recent developments in string theory, supersymmetry and quantum gravity. The volume comprises two different sections. The first consists of five pedagogical reviews by prominent physicists, covering the currently important subjects of supermembranes, duality, D-branes, new non-perturbative methods and string phenomenology. The second section consists of research reports in these areas and also on other currently important topics such as supersymmetric gauge theories, two-dimensional quantum gravity...