Festkörper Probleme IX: Advances in Solid State Physics presents a model for the behavior of electrons in non-crystalline materials. This book describes some experimental evidence that supports for the behavior of electrons. Organized into 16 chapters, this book begins with an overview of crystallization, glass forming, and melting processes in systems forming chalcogenide glasses. This text then describes the theory of the transport properties of electrons in non-crystalline solids and liquids. Other chapters consider the optical and electrical properties of amorphous semiconductors wherein the treatment is mainly restricted to the elements selenium, germanium, and tellurium. This book discusses as well the basic aspects of the optical phenomena of the Jahn–Teller effect, with emphasis on some criteria of the strength and observability of the Jahn–Teller effect. The final chapter deals with the methods for processing emulsion and metal film masks. This book is a valuable resource for solid state physicists.