This volume is a collection of experimental and theoretical papers presented at the international "Topical Meeting on Optical Bistability", held at the University of Rochester, June 15-17, 1983, sponsored jointly by the Air Force Office of Scientific Re­ search; the Army Research Office; and the Optical Society of America. The Conference, which had 150 attendees, overlapped (on June 15) with the Fifth Rochester Conference on Coherence and Quantum Optics with two joint sessions. Some of the topics cover­ ed in this volume are also treated io the Proceedings of that Conference. Since the last international conference on Optical Bistability, held in Asheville, North Carolina, June 3-5, 1980, there have been new and important fundamental advances in the field. This is borne out in papers in this volume dealing with optical chaos and period doubling bifurcations leading to chaos as well as the report of results of an experiment using a very simple system exhibiting ab­ sorptive optical bistability in a ring cavity using optically pump­ ed sodium atoms, which was successfully analyzed quantitatively by a simple theory. Other advances discussed here include the ob­ servation of optical bistability due to the effect of radiation pressure on one mirror of a fabry-Perot cavity. and the prediction of mirrorless intrinsic opittal bistability due to the local field correction incorporated into the Maxwell-Bloch formulation. Advances in optical bistability in semiconductors relate closer to actual device applications.