The dynamic developments in high-temperature superconductivity over the last three years has augmented the importance of materials research not only for applications, but also for the understanding of underlying physical phenomena. The discovery of new superconductors has opened up new facets of High Tc research, and the perfection of already known materials has enabled reliable physical measurements to be carried out, providing a foundation for theoretical models. The papers in this volume present an overview of the recent developments in the field of High Tc-materials research. One of the highlights of this meeting was the plenary lecture by the Nobel laureate K. Alex Müller on the importance of the apical oxygen phenomena which are strongly connected with Tc changes.