There is a curious link in the origins of rock music, that takes it back to a form of early jazz known as "jug band music." In England, a teenaged band from Liverpool known as The Quarrymen jumped on the "skiffle" craze in the mid-50s, and their leading members eventually became the nucleus of The Beatles. Meanwhile, "across the pond" in America, a number of folk music enthusiasts in the late 50s and early 60s got into the genre, with a hint of the Southern blues. Towards the end of that phase, a young guitarist named John Sebastian, the son of a famous harmonica player of the same name, teamed up with fellow-guitarist Zal Yanovsky. Together with drummer Joseph Campbell Butler and bassist Steve Boone, they formed a band whose name was inspired by a Mississippi John Hurt tune.
The Lovin' Spoonful was part of the American response to the "British Invasion." Even with hard-hitting tunes like "Summer in the City," they never lost their roots in the "roots music" of America. Such is evident in this clip from CBS' The Ed Sullivan Show. The tune "Nashville Cats" has Sebastian playing the autoharp, an instrument otherwise reserved to folk and mountain music. It was "thinking outside the box" then, and still would be today.
One thing led to another, and the band fell apart by the end of 1968. Sebastian continued with a respectable solo career. Today, he is one of the most popular artists providing musical instruction in autoharp, guitar, and yes, harmonica, for the New York-based Homespun Tapes.
I personally remember watching this performance in 1967: "Yes I was just thirteen, you might say I was a musical proverbial knee-high, when I heard a couple new soundin' tunes on the tube and they blasted me sky-high..." I remember my dad commenting on Sebastian having a nice singing voice. It was an unusual observation in light of the genre, in relation to the source.