A Connoisseur's Case is a 1962 detective novel by the British writer Michael Innes. It is the eighteenth in his series featuring John Appleby of Scotland Yard. It is a country house mystery, harking back to the Golden Age of Detective Fiction. It was released in the United States by Dodd, Mead under the alternative title The Crabtree Affair. It was adapted into an episode of the television series Detective with Appleby played by Dennis Price.