What's New is a ballad composed by Bob Haggart, with lyrics later added by Johnny Burke. Haggart, a bassist, arranger, and composer in Bob Crosby's Orchestra, wrote the tune in 1938 as an instrumental originally titled I'm Free, specifically to feature trumpeter Billy Butterfield. He reportedly composed and recorded it with the band on the same day. Burke's lyrics, added in 1939, transformed it into a vocal ballad whose opening line gave the song its lasting title. The melody is lyrical and sustained, with smooth harmonic motion that incorporates modulations lending emotional depth without excessive complexity. These qualities have made it a natural vehicle for soloists, whether on trumpet, saxophone, or voice, and it has become a widely performed jazz standard. The composition's elegance and harmonic richness invite a range of interpretive approaches, from slow, introspective ballad readings to medium-tempo swing treatments. Notable recordings span decades and styles, including Paul Chambers's 1957 quintet session with Clifford Jordan, Donald Byrd, and Tommy Flanagan, Roy Hargrove's 1991 version on Public Eye with Antonio Hart and Stephen Scott, and Emmet Cohen's 2022 live recording featuring Stacy Dillard on tenor saxophone. The tune has generated significant royalties for Haggart over the years, a testament to its enduring appeal across both jazz and popular music contexts.