Gaston Leval (born Pierre Robert Piller October 20, 1895 - April 8, 1978) was an anarcho-syndicalist, combatant and historian of the Spanish Revolution.
The son of a French Communard, Leval escaped to Spain in 1915 to avoid conscription during the First World War. There he joined the anarcho-syndicalist Confederación Nacional del Trabajo trade union. Leval left for Argentina during the dictatorship of Primo de Rivera where he would live from 1923 to 1936, returning to Spain to document the revolution and the urban and rural anarchist collectives.
- Gaston Leval, "Anarchists Behind Bars", Summer 1921
- Gaston Leval, "Collectives in Aragon", London, 1938
- Gaston Leval, "Social Reconstruction in Spain: Spain and the World", London, 1938
- Gaston Leval, "Ne Franco Ne Stalin", Milan, 1952
- Gaston Leval, "Collectives in the Spanish Revolution", Freedom Press, London, 1975 (originally in French, "Espagne Libertaire (1936 - 1939)", Editions du Cercle, 1971)