Jean Cassou (9 July 1897 – 16 January 1986) was a French writer, art critic, poet, member of the French Resistance during World War II and the first Director of the Musée National d'Art Moderne in Paris.
Jean Cassou was born at Deusto, near Bilbao, (Spain). His father was French (with a Mexican mother) and his mother Milagros Ibañez Pacheco was from Andalucia (Spain).
His father, who had the prestigious degree Ingénieur des Arts et Manufactures, died when Jean was only sixteen. His mother gave Jean and his sister basic Spanish culture, and he learnt French and Spanish classics side by side at school. Jean did secondary studies at the Lycée Charlemagne while providing for the needs of his family, then began study for the Licence d'espagnol (Spanish) degree at the Faculty of Letters in Paris. This he followed in 1917 and 1918 by getting a master's degree at the Bayonne Lycée and, though interrupted many times, was not mobilised in World War I. He was Secretary to Pierre Louÿs, writing from 1921 to 1929 his monthly chronicle "Spanish Letters" in the cultural magazine Le Mercure de France (of which he was editor). He became in 1923 the writer for the Ministry of State Education and in 1926 published his first novel.
In 1932 Jean Cassou became an inspector of historic monuments. In 1934 he became a member of the Vigilance Committee of anti-fascist intellectuals and director from 1936 of the review Europe. In 1936 he was a member of the cabinet of Jean Zay, Minister of State Education and of the Art-schools of the Popular front. He was then in favour of the Spanish Republic and socialism, and approached the communist party – but broke with then in 1939 at the time of the Germano-Soviet pact. On the approach of the German army, he went to the castle at Compiègne and devoted himself to the safeguard of the national heritage.