Muir was a doctor and sailor. After his time aboard "Tiger" (which he writes about in the book in the Collection (q.v.)) he was appointed Medical Officer in charge of British Weihaiwei on the north-east coast of China.
In the Second World War, at the age of 66 and by then retired, he was commissioned a sub=lieutenant RNVR and appointed as navigator and watchkeeper of HMS Campeador V, a vessel of the Auxiliary Patrol Service. In June 1940 she was blown up by an enemy mine while patrolling off Portsmouth. Muir was among those killed.
