Chalcogenide glasses are promising photonic materials due to their unique properties and functionalities. Chalcogenide glasses are transparent from visible to near-infrared wavelengths and can be shaped into lenses or drawn into fibres. They have useful commercial applications as lenses for infrared cameras, and chalcogenide glass fibers and optical components are used in waveguides for lasers, optical switching, chemical and temperature sensing, and phase change memories. Chalcogenide glasses provides a comprehensive review of the most recent technological advances in this field as well as industrial applications of the technology. Part one describes the preparation methods and properties of chalcogenide glasses, such as their thermal, structural, and optical properties, before moving on to mean coordination and topological constraints in chalcogenide network glasses, as well as photo-induced phenomena in chalcogenides. This section also discusses chalcogenide glasses' ionic conductivity and physical aging, as well as chalcogenide thin film deposition techniques and transparent glass-ceramics. Part two investigates the applications of chalcogenide glasses.