Doo-wop is a jazz and blues hybrid that's recognized for its vocal group harmony. It's a genre of music that was dominated throughout the 50s and 60s. Doo-wop music was typically structured with a tenor lead vocalist performing the melody and a trio or quartet providing backing harmony. During a song, Doo-Wop frequently incorporates both a cappella vocal harmonies and full swing-like rhythms.
Doo-wop's origin may be attributed to the Mills Brothers and the Ink Spots' albums from the 1930s and 1940s. This is because the Mills Brothers utilized their vocal harmony to replicate the sound of instruments in many of their recordings. They also made small-group harmony into an art form.