John Grierson (1898–1972) was a pioneering Scottish filmmaker and producer who shaped the documentary film movement, earning recognition as the father of British and Canadian documentary cinema. He famously coined the term "documentary" in 1926 and championed the idea that film should serve as a tool for social education and reform. As the driving force behind the British documentary movement, he founded the GPO Film Unit, which produced groundbreaking works like Night Mail (1936), and later played a key role in establishing the National Film Board of Canada (NFB) in 1939, turning it into one of the world's most influential documentary institutions. Grierson’s vision and advocacy for documentary as a vehicle for public service and civic engagement left a lasting legacy on global nonfiction filmmaking.