The discovery of high temperature superconductivity has not only opened many possibilities for potential technical applications, but has also provided a unique, challenging research subject for condensed matter physics and material sciences. High temperature superconductivity appears in systems with strong electron correlation and constitutes one of the key issues in condensed matter physics. The understanding of its mechanism will therefore greatly promote the future developments of this branch of science. During the last ten years great progress has been made in both fundamental and application-oriented research. Expanding knowledge of the physical properties in the superconducting as well as the normal state in preparing the way to an understanding of the underlying mechanisms. The accumulated experience in materials processing enables technical applications. All these aspects of high-T superconductivity and recent work on 'traditional' superconductors have been exposed at the Beijing conference. The present volume is a separate edition of part I of the extensive Proceedings of the Fifth International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors. It contains the plenary, tutorial and invited papers, and gives a comprehensive account of the state-of-the-art as of March 1997.