Stuart Mason was born in Chislehurst, Kent in 1919. He attended Winchester College and Caius College, Cambridge, graduating in 1943. His clinical studies were carried out at the London Hospital in Whitechapel.
He wrote extensively for a wide range of audiences. In addition to a series of original scientific research papers, he was responsible for four medical text books which helped establish the specialty of endocrinology and three editions of the undergraduate text book Hutchinson's Clinical Methods.
He had the rare distinction of starting three new journals. In 1966 he was invited by the president of the RCP to edit the Journal of the Royal College of Physicians (JRCP) which he did until 1987. His other research interest was history. In the JRCP he wrote a series of historical vignettes, many of which were later turned into major articles or lectures. He particularly became interested in the history of the RCP, publishing his book on George Edwards and his birds in 1992.
His enormous appetite for research and writing found a new outlet in retirement when he combined his love of maps with a devotion to the local history of Essex. He continued writing up until his death and in 1999 won the inaugural Local History Award for his article Summer camps for soldiers in Essex.