I recently read that John Stewart died in January. My daughter and I saw him in Portland, OR last spring and he was a very old 67 year old person with a very frail voice but a strong spirit.
John Stewart was a songwriter's songwriter. His 1969 California Bloodlines album is considered one the greatest american albums of all time. He could be compared to Woody Guthrie or Jack Kerouac. He invented a musical form called americana which took influences from folk, rock, blues and country. His songs were recorded by several artists and made into hits.
Before he went solo he was in the Kingston Trio from 1961 until 1967. He had a hit with Gold aided by members of Fleetwood Mac but fame always eluded him. Maybe it was better that way.
Here is a 1966 YouTube clip of John with the Kingston trio. He's the one in the middle.