Born in London on 27 April 1887, second son of John McNair of Paisley, an underwriter at Lloyds, he was educated at Aldenham School, Emmanuel College, Cambridge where he took second-class honours in Natural Sciences, and at Guy's Hospital. During the first world war he served with the Royal Navy and then as a surgical specialist with the RAMC in the Indian Expeditionary Force D in 1916 and later in the Afghan fighting. He returned to Guy's after the war, and served the hospital and its medical school for thirty years, specialising in obstetrics and gynaecology. When he retired in 1952 the hospital conferred on him the title of emeritus, and later that year St Thomas's Hospital appointed him their honorary consulting gynaecologist. Before he retired he had also held appointments at the City of London Maternity Hospital, North Herts and South Bedfordshire Hospital, Purley Memorial Hospital, and at Caterham and District Hospital. McNair was a foundation member of the Royal College of Obstetricians and Gynaecologists and was elected a Fellow in 1931. He then served on the council and on many College committees and was elected vice-president. When he retired from his active hospital practice in 1952 he was elected honorary librarian where a great deal of his time was spent in arranging a large collection of old books and manuscripts in the library. He was President of the section of obstetrics and gynaecology at the Royal Society of Medicine in 1947, and an active member of the Gynaecological Club. Though he shunned publicity, his influence was wide and he helped to shape the course of modem obstetric care. He had a dry sense of humour, was well read with an excellent memory, and used these gifts to enliven his teaching. In younger days he was a keen sportsman, rowing, cycling, boxing, running, fishing and playing Rugger. McNair lived at 9 Devonshire Mews West, and died on 30 May 1964 aged 77; he had married Grace Mary Buist in 1930, and was survived by her and their three daughters.