The version of Gershwin’s Porgy and Bess known to the world may not be the version he intended to be the final one. “It turns out that Gershwin, during rehearsals for the New York premiere at Broadway’s Alvin Theatre, made extensive cuts and additions to his 700-page score. Since the composer died only two years later, in 1937, that edited but unpublished version represents, in effect, his final word on the subject.”