This book is one of a series reporting on international research and development activities conducted by the Schott Group companies. With the series Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glass and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subject treated. This volume lays the foundations for - supervision of production processes, including raw materials, evaporation from the melt, exhaust gases, and environmental concerns; - troubleshooting in case of glass defects in combination with research for the design of faultless (in the ppm range) or at least high-yield processes; - understanding the origin of customer complaints because of unfulfilled expectations concerning material properties or product behaviour. The book is conceived as a monograph. The individual chapters, however, are written by leading Schott experts on the corresponding subjects. Many figures, tables, and examples are chosen to introduce the reader to thin-film science and technology.