Ken Riley is a retired Lecturer in Physics at the University of Cambridge Cavendish Laboratory. He is also a Fellow of Clare College, Cambridge, where he was both the Senior Tutor and Admissions Tutor, and taught physics and mathematics for over forty-five years. He has served on many committees and panels concerned with the teaching and examining of these subjects at all levels of tertiary and university education. His research was centred on nuclear physics at Harwell and then elementary particle physics at Brookhaven, New York, the Rutherford Laboratory and Stanford.