John Hay Beith was a British novelist and playwright who wrote under the pseudonym Ian Hay. A graduate of Cambridge, Beith initially worked as a schoolmaster, but gave up teaching when his writing became commercially successful. Beith served as an army officer in France during the First World War, and his humorous portrayal of army life, The First Hundred Thousand, was a bestseller upon publication.

After the war, Beith s novels would never sell as well again, but he d developed an interest in the theatre and wrote or co-wrote a number of long-running light comedies, as well as adaptations and original screenplays for the cinema. His collaborators included Guy Bolton and P.G. Wodehouse. Beith died in 1952.