Thomas Daniel Calnan (16 December 1915 – 13 September 1981) was an English pilot and prisoner-of-war of World War II, who wrote a memoir of his time in German captivity entitled Free As A Running Fox. Calnan was commissioned in the RAF on 19 December 1936. Calnan was shot down while flying a Spitfire on a photo-reconnaissance mission over France in December 1941. He gives some brief background about himself and his flying career with the RAF's No. 1 Photographic Reconnaissance Unit, but devotes most of the book to his escape attempts while a prisoner of the Germans. He was incarcerated at Stalag Luft III during the period of the "Great Escape." He was promoted to the rank of Wing Commander on 1 January 1949, and retired on 14 February 1959. Calnan latterly lived in Zinal, Switzerland, where he died in September 1981 at the age of 65.