I Wish I Knew is a 1945 jazz standard composed by Harry Warren with lyrics by Mack Gordon. It was introduced in the Twentieth Century-Fox film Diamond Horseshoe (1945), where Betty Grable and Dick Haymes perform it with an orchestra led by Victor Young. The first recording took place on January 21, 1945, and a 1945 release followed for Dick Haymes’s version, with Harry James and His Orchestra featuring Kitty Kallen issuing a version on April 9, 1945. Over the decades it has been recorded by a wide range of artists, including Chet Baker, Bud Shank, Russ Freeman, Nat King Cole, Della Reese, Bill Evans Trio, John Coltrane Quartet, Ahmad Jamal, Petula Clark, Joni James, and many others, making it a staple of the jazz standards repertoire. The tune is a romantic ballad with a lush melody and sophisticated harmony, suitable for both vocal and instrumental performances.
