"Don't You Know?" is a 1959 popular song by written by Bobby Worth, and hit record for singer Della Reese. The song was adapted from an aria ("Musetta's Waltz") from Puccini's La Boheme. It became Reese's biggest hit, reaching number two on the U.S. Pop chart and number one on the U.S. R&B chart. The song was a follow-up to her previous big hit "And That Reminds Me". The song was Reese's first single on her new label RCA Victor. The song helped Reese get a nomination for a Grammy Award for Best Female Vocalist. It also led to nine years in Las Vegas.