The inevitability of gravitational collapse for stellar bodies of sufficient mass was convincingly demonstrated by S. Chandrasekhar in the 1930s, black holes and neutron stars played a minor role in serious analyses of physical or astrophysical phenomena until the discovery of quasars and pulsars in the 1960s. Black holes and neutron stars are now generally recognized as key components of many astrophysical systems, and play a central role in the understanding of gravitational phenomena at both the classical and quantum levels. Based on a symposium held in honour of S. Chandrasekhar, these papers provide a comprehensive summary of progress made in the 1990s on the theory of black holes and relativistic stars.