The Brothers Four
Most accounts of the post-WWII folk music boom focus on the political and issue-oriented branch of the music, embodied by Woody Guthrie and Bob Dylan, at the expense of the softer, more entertainment-oriented branch, embodied by the likes of the Kingston Trio, the Chad Mitchell Trio, and the Brothers Four. Those acts and the music they made -- though it sold well and, indeed, for many years defined what most Americans visualized when the phrase "folk music" was mentioned -- are scarcely mentioned in most histories; the Brothers Four aren't even listed in the Guinness Who's Who of Folk Music.