John Denton has made many important contributions to the study of flows in turbomachinery. He developed a ‘through-flow’ computer program for calculating the flow in steam turbines, testing it on an experimental turbine, and making studies of losses, secondary flows and tip clearance effects. His outstanding contribution subsequently has been the development of a series of fully three-dimensional time-marching programs, which have been used all over the world for calculating the flows in existing steam and gas turbines and for the design of new machines. His flair as a designer of fans and turbines for aircraft engines and power plants as been widely recognised.