In the past two years conferences on superconductivity have been characterized by the attendance of hundreds of scientists. Consequently, the organizers were forced to schedule numerous parallel sessions and poster presentations with an almost unsurveyable amount of information. It was, therefore, felt that a more informal get-together, providing ample time for a thourough discussion of some topics of current interest in high-temperature superconductivity, was timely and benefitial for leading scientists as well as for newcomers in the field. The present volume contains the majority of papers presented at the International Discussion Meeting on High-Tc Superconductors held at the Mauterndorf Castle in the Austrian Alps from February 7 to 11, 1988. Each subject was introduced in review form by a few invited speakers and then discussed together with the contributed poster presentations. These discussion sessions chaired by selected scientists turned out to be the highlights of the meeting, not only because all the participants truly appreciated the possibility of an information exchange, but mainly because of the magnificent job done by the discussion chairmen, John A. Mydosh (Leiden), Martin Peter (Geneva) and Ken E. Gray (Argonne). First results on the just discovered Bi-superconductors and the clarification of electron resonance experiments on (123)-compounds should be mentioned in particular. The relaxed atomosphere favoring free discussions was certainly promoted by the surroundings offered in the Mauterndorf Castle, which dates back to 1253. Poster presentations and a conference banquet in historic knight's halls are certainly not found everyday in conference routines.