Since the discovery of high temperature superconductors the scientific com nmnity has been very active in research on material and system development as well as on the basic understanding of the mechanism of superconductiv ity at high transition temperatures. Industrial groups joined in very soon as with these new materials the prospects for commercial application of super conductivity seemed to be more promising than ever. Materials processing was divided into film deposition and bulk preparation techniques, the latter including conductor fabrication and melt growth of monolithic samples as well. Because of the high impact of possible applications in energy technol ogy, wire and tape fabrication of the BSCCO superconductors is one of the most important fields, in addition to thin film technology for mobile comuni cation. Only since processes like IBAD and RABiTS TM were invented have film deposition techniques also become important for energy technology. In order to produce suitable conductors with material properties which meet the challenge imposed by energy technology, detailed understanding of the phase formation and physical properties of the high temperature super conductors is necessary. The goal of this book is on one hand to provide the basic information on phase formation and physical properties, and to give a short overview of the state of the art in conductor preparation and character ization. On the other hand it contains the authors own results in the field of preparation and characterization.