Bob Haggart was an American bassist, composer, and arranger whose work helped shape the sound of swing-era jazz and left behind several enduring standards. Born in New York City in 1914, he came to prominence as a member of Bob Crosby's orchestra in the 1930s, where he served as both bassist and chief arranger. His most famous composition, originally titled I'm Free, was given lyrics by Johnny Burke and renamed What's New. First recorded in 1938, the song became one of the most widely performed ballads in jazz, covered by artists ranging from Bing Crosby and Charlie Parker to Linda Ronstadt. Haggart also co-wrote two swing-era staples with drummer Ray Bauduc: South Rampart Street Parade and Big Noise from Winnetka, the latter featuring a celebrated duet between bass and drums. His arranging career extended well beyond the Crosby band, encompassing sessions for Louis Armstrong, Billie Holiday, Ella Fitzgerald, Sarah Vaughan, and Duke Ellington. With trumpeter Yank Lawson, he co-led the Lawson-Haggart Jazz Band and later the World's Greatest Jazz Band, for which he produced dozens of arrangements. Haggart remained active for over six decades, contributing to jazz as a performer, writer, and arranger until his death in Venice, Florida, in 1998.