The Affair at the Semiramis Hotel is a 1917 detective novella by the British writer A. E. W. Mason featuring his character Inspector Hanaud. Mason had originally written many of the plot elements for an abortive silent film, to be called The Carnival Ball. The novella appeared between Mason's first full-length Hanaud novel, At the Villa Rose (1910), and his second, The House of the Arrow (1934).
Alfred Edward Woodley Mason (7 May 1865 – 22 November 1948) was an English author and politician. He is best remembered for his 1902 novel of courage and cowardice in wartime, The Four Feathers and is also known as the creator of Inspector Hanaud, a French detective who was an early template for Agatha Christie's famous Hercule Poirot. His prolific output in short stories and novels were frequently made and remade into films during his lifetime; though many of the silent versions have been lost or forgotten, the productions of Fire Over England (1937) and The Four Feathers (1939) remain enduring classics of British cinema.