Amorphous silicon technology has been the subject of symposia every year since 1984. This remarkable longevity is due to the continuous emergence of new scientific questions and new technological challenges for silicon thin films. Earlier there was a strong emphasis on methods to achieve high deposition rates using plasma or hot-wire chemical vapor deposition, and on the properties and applications of nanocrystalline silicon films, which for example have been incorporated into stacked a-Si:H/nc-Si:H solar cells. The papers appearing in this book are sorted under six chapter headings on the basis of subject matter. Chapter I is concerned with amorphous network structures, electronic metastability, defects, and photoluminescence. Chapter II focuses on thin-film transistors and imager arrays. Chapter III covers solar cells. Chapter IV addresses growth mechanisms, hot-filament CVD, and nc-Si:H growth. Chapter V contains all remaining topics in film growth, especially those related to devices. Finally, Chapter VI focuses on crystallized film.