This release has long been considered Thelonious Monk's acknowledgement to the flourishing youth-oriented subculture from whence the collection takes its name. Certainly the Grammy-winning cover - which depicts Monk as a World War II French revolutionary toting an automatic weapon - gave the establishment more than the brilliant swinging sounds in the grooves to consider. Underground became Monk's penultimate studio album, as well as the final release to feature the '60s quartet: Charlie Rouse, Ben Riley, and Larry Gales. This 180gram audiophile-grade pressing was mastered from analog tapes. Each jacket in this limited edition pressing of 2,000 copies is numbered with a gold foil stamp.