“Stayin’ Alive” is heard over the opening credits of Saturday Night Fever in 1977, while John Travolta walks with that signature swagger through the streets of New York. The film ended up becoming almost synonymous with the disco era, and along with it “Stayin’ Alive” became one of the songs identified with disco more than almost any other. The Bee Gees were already singing in a high falsetto from 1975’s “Jive Talkin’,” which was also on the soundtrack, but before that they were already huge as a vocal harmony group in the late 60s and early 70s. Their contribution to Saturday Night Fever launched them into another level, but at the same time stuck them with the label of “disco singers.”