We have in this volume, compiled a connected account of the proceedings of the Symposium on Wolf-Rayet and High-Temperature Stars held at Buenos Aires. The Organizing Committee had assigned broad areas of topical interest to be reviewed by invited speakers. Each of these presentations was followed by lengthy discussions that were tape recorded and transcribed later. These discussions have been edited only to a limited extent. We have shortened them and rearranged them to bring about a greater coherence. We have, however, attempted to retain the tenor of the discussions, the flavour of impromptu remarks and the continuity of an argument. Much of the success of such a venture depends on the contributors to the discussions. To be able to make these thoughts available to a larger audience has been the task of those re­ sponsible for the elaborate tape recording of the proceedings. We thank those at the Instituto de Astronomia y Fisica del Espacio for the efficient way in which this re­ sponsibility has been discharged. Many at Buenos Aires and Kodaikanal have contrib­ uted efficient assistance to the preparation of this volume and we are deeply indebted for their help. In particular, two amongst these, Nora Martinez and A. M. Batcha have contributed overwhelmingly both to the organization of the symposium and the final preparation of the symposium volume. Financial support for this symposium came from the International Astronomical Union and the Argentine National Research Council.

Section I.- The Wolf-Rayet Stars - The General Problems of Extended Atmospheres and Non-Classical Atmospheric Models.- Section II.- Classification and Distribution of WR Stars and an Interpretation of the WN Sequence.- UV and Radiofrequency Observations of Wolf-Rayet Stars.- Effective Temperatures of Wolf-Rayet Stars.- Section III.- The Spectra of Wolf-Rayet Stars at High Dispersion.- Section IV.- O and Of Stars.- Some Relations Between Wolf-Rayet and P Cygni-Type Stars.- Nuclei of Planetary Nebulae.- Section V.- Evolutionary Aspects of Wolf-Rayet Stars.- Section VI.- Theory of Wolf-Rayet Spectra.- Section VII.- Wolf-Rayet Binaries and Atmospheric Stratification.- An Interpretation of the WC Stars.- Section VIII.- Summary of Problems and Conclusions on the Nature and Physical Structure of Wolf-Rayet Stars.