The late, legendary Pink Floyd founder Syd Barrett remains one of the most enigmatic figures in rock music, and a new anthology of his work, An Introduction to Syd Barrett, is only likely to further the myths and mysteries surrounding the iconoclastic artist, who died in 2006.

Of particular interest to Barrett fans will be the anthology’s inclusion of a never-before released track, “Rhamadan,” which is available as a bonus download to those who purchase the album.

The track is drawn from the tumultuous sessions for Barrett’s 1970 solo album, The Madcap Laughs, and is a prime example of Barrett’s most noncommercial instincts. “Rhamadan” is essentially a 20-minute, freeform jam, with Barrett forsaking melody and structure as he solos on a variety of instruments.

According to some recollections, the only other musician contributing to the track is Steve Peregrine Took, the percussionist in the original lineup of Marc Bolan’s Tyrannosaurus Rex. As for vocals, Barrett is silent but an engineer can be heard kicking things off by calling out, “‘Rhamadan,’ Take one!” As with so much of Barrett’s work, it’s almost impossible to imagine what would have happened on a “Take two.”