Muir was born in
Balfron, Scotland, and subsequently attended Glasgow University where he studied geography and archaeology. His first job was as a language teacher in Pforzheim in Germany.
He worked as a philatelic journalist and Editor on Stamp Collecting, the Philatelic Magazine and then the British Philatelic Bulletin. He was also the founder of the Postal Mechanisation Study Circle. He has been a Trustee of the Stuart Rossiter Trust from 2013.
Publications
An Introduction to British Postal Mechanisation, Postal Mechanisation Study Circle, 1979. (With Martin Robinson)
Postal Reform and the Penny Black: A New Appreciation, National Postal Museum, London, 1990.
ISBN0-9515948-0-X