12-String Blues was recorded live in 1968 at the Ten O’Clock Scholar, a Minneapolis coffee house that had also featured Bob Dylan, Spider John Koerner and Simon & Garfunkel early in their careers. Many of the songs were re-recorded in 1970 on Kottke’s 3rd album, Circle Round The Sun. The following info was taken directly from wikipedia.org:

Leo Kottke (born on 11 September 1945 in Athens, Georgia, U.S.) is widely known for his idiosyncratic fingerpicking style, which draws on blues, jazz, and folk music influences, and his syncopated, polyphonic melodies. His work is often considered part of the American Primitivism movement, partly because he was signed to John Fahey’s Takoma Records label. Kottke has overcome a series of personal obstacles including partial deafness and a nearly career-ending bout with tendon damage to emerge as a widely-recognized master of his instrument.

As a youth living in Muskogee, Oklahoma, Kottke played trombone and violin before moving to the guitar and developing his own unconventional picking style. A mishap with a firecracker permanently damaged his hearing in one ear, a condition that would be exacerbated during firing practice during his service in the United States Navy Reserve.

After being discharged from the Naval Reserve, Kottke attended St. Cloud State University in central Minnesota where he was known for skipping class and instead going to the auditorium and playing his guitar for hours on end.

Focusing primarily on instrumental composition and playing, Kottke has sporadically moved in a vocal direction, singing in an unconventional yet expressive baritone famously self-described as sounding like “geese farts on a muggy day”. In concert, Kottke intersperses humorous and often bizarre monologues with vocal and instrumental selections from throughout his career, played solo on his signature 6- and 12-string guitars. Kottke’s guitars are often tuned unconventionally; early in his career he heavily utilized open tunings, while in recent years he has used more traditional voicings but often detunes his guitars as many as two full steps below standard tuning.

In the early 1980s, Kottke began to suffer from painful tendinitis and related nerve damage caused by his vigorous and aggressive picking style (particularly on the 12-string guitar). As a result, he changed his picking style to a classical style, using the flesh of his fingertips and increasingly small amounts of fingernail rather than fingerpicks, and changing the positioning of the right hand which places less stress on the tendons. He also studied more classical and jazz-oriented compositional and playing techniques. Simultaneously, Kottke moved from his relationship with major labels Capitol and Chrysalis to the smaller Private Music label.