I was involved in the early research on electrical switching devices based on semiconducting chalcogenide glasses which generated such widespread interest during the later '60s and early '70s. There was great controversy at the time about the extent to which the switching mechanism is controlled by purely electronic process or is thermally induced. Papers A1, A2 and A4 summarise my contribution, the last (A4) setting out in detail the view that electrical switching in the chalcogenide glasses is basically an electrothermal process. By the late '70s it became clear that chalcogenide-based switching devices would not find major applications in mainstream electronics but the collaboration with the Dundee group on the application of amorphous silicon in similar devices has proved to be extremely fruitful. The first results are contained in paper A5, and A17 is a comprehensive review of that work, set in the general context of electronic switching in amorphous semiconductors. Concurrently, interest in chalcogenide glasses switched (!) to possible utilisation of their unique photo-induced effects. This is also proving to be a fruitful field. Potential applications include photoresists for high resolution microlithography, diffraction gratings - particularly for the infra-red, and in various non-linear electro-optic devices, also in the infra-red. Papers A8, A10 and A11 are typical original contributions; paper A16 is a general review.