Robert William Lamm is an American musician and a founding member of the rock band Chicago. He is best known for his songwriting, vocals, and keyboard melodies, most significantly on the band's debut studio album, Chicago Transit Authority (1969). Lamm wrote many of the band's biggest hits, including "Questions 67 & 68", "Does Anybody Really Know What Time It Is?", "Beginnings", "25 or 6 to 4", "Saturday in the Park", "Dialogue " and "Harry Truman". Lamm is one of three founding members still performing with the group.

Chicago is an American rock band formed in Chicago in 1967. The group began calling themselves the Chicago Transit Authority in 1968, then shortened the name in 1969. Self-described as a "rock and roll band with horns," their songs often also combine elements of classical music, jazz, R&B, and pop music.