Lionel Mapleson was the Metropolitan Operaʼs librarian from the 1890s until he died in 1937. In 1900, he purchased an Edison “Home” Cylinder Phonograph, smuggled the gadget into the prompter’s box, and started recording excerpts from Metropolitan performances. In 1904, Mapleson’s piratical activities came to an end, but by then he had amassed an extraordinary collection that has been called one of the most valuable legacies in the history of recorded sound.