Born the son of a headmaster in Cambusbarron, near Stirling, John Grierson directed one of the first documentaries, Drifters, set up the influential GPO Film Unit making Night Mail, and went on to be the first director of The National Film Board of Canada.
The annual awards for best documentary are made in his name. He set out to make films to change the world, and made not just films, but filmmakers.
Watch the documentary Thursday 22, BBC2 Scotland, 22:00