I was fortunate that, about the time that I left the mastership at Caius and wished to devote more time to physics, interest was developing in non-crystalline semiconductors. This was a new branch of solid state physics, in which it was possible to lay the foundations without unduly sophisticated mathematics, and to carry out experiments with relatively cheap equipment. The position was similar to that in crystalline semiconductors in the 1930s. From 1965 onwards research in this field was my main activity, as it could not have been had I remained a college Master, and for this work I shared a Nobel prize for physics in 1977. I will next describe the nature of this work, how I came to be involved in it and what it achieved.