John Cotes’ book, Lung Function, has for 50 years been required reading for all who practise respiratory physiology. To those running lung function laboratories or undertaking research in the field, it has been indispensable. The appearance of a new addition deserves to be placed in its historical context.

Cotes wrote Lung Function in the 1960s as, in some ways, a response to Comroe’s The Lung. The latter book achieved an extraordinary fame by presenting complex ideas in visual form, simplifying the conceptual background and, in the 2nd edition, confining all mathematics to a lengthy appendix. Cotes’ book was less easy to read, much more practical, and did not underplay the problems of this difficult subject. I bought the second edition of Cotes’ book in 1972; I have it still and the margins are littered with pencilled notes and expansions of formulae and equations. Being a weak mathematician, I did not find the book entirely satisfactory and turned to Ken Saunders’ book Clinical Physiology of the Lung for extended explanations of, for example, the oxygen–carbon dioxide diagram. This was then the great test! Riley had contributed a brilliant mathematical exposition in the 19th edition of Ruch and …