John Cotes died on 15 April 2018, aged 94. Working at the RAF Institute of Aviation Medicine, Farnborough (1950-2) then the MRC Pneumoconiosis Research Unit (PRU), Llandough (1953) his research concerned the design of an oxygen delivery system for the 1953 British Everest expedition. Oxygen equipment had a daunting reputation following failures on previous expeditions. As sole author of his first paper, he described an improved design and production of the oxygen masks and open circuit oxygen breathing circuits fundamental to the first successful Everest Summit. A member of The Society since 1954, he was well-known for his work on patients with industrial and other lung diseases at the PRU. Later, at the University of Newcastle, he developed systems to evaluate pulmonary function at rest and exercise, particularly lung gas transfer. The 6th Edition of his well-known text book, Lung Function: Physiology, Measurement and Application in Medicine, appeared in 2006.