John Martyn led a tumultuous life and suffered from substance abuse for a good part of it. That being said, he was an extraordinary and innovative acoustic guitarist. I saw John Martyn in person could not have been more impressed by his style, technique, and ability. On Solid Air, his improvisation and collaboration with other musicians, especially the great Danny Thompson, was magical. I remember hearing Martyn play his guitar through an Echoplex for the first time - he brought a progressive influence to acoustic folk. Martyn achieved commercial success (23 albums), and when he didn't play solo, opened for many great bands and artists at one time or another, including Eric Clapton, Traffic, and Yes.