The Everly Brothers were responsible for introducing a country style of harmony singing into rock'n'roll. While DonEverly (), sang tenor, his brother Phil (), sang high, keening harmonies. The brothers based their style on the singing of Appalachian groups such as The Blue Sky Boys and The Louvin Brothers. The Everly Brothers updated the sound for the 1950s, singing songs of teenage romance backed with a rock'n'roll beat. During the late 1950s...