The two sets of 12 pieces for amplified piano, completed in 1972 and 1973, are among Crumb's best known. The title makes reference to Bart‹k's Mikrokosmos, and the format is a nod both to that set and to Debussy's 24 Preludes. Subtitled "Fantasy-Pieces After the Zodiac," each of the 24 pieces is associated with a friend of Crumb born under a particular Zodiacal sign.

Leng Tan is a specialist in contemporary music and in the work of John Cage in particular. "For me, George Crumb, along with John Cage and Henry Cowell, form the triumvirate of 'the three Cs,' the three intrepid American pioneers of 20th-century avant-garde pianism," she writes in her program notes. "Their explorations of the extended and orchestral possibilities of the piano, while considered maverick at the time, have now achieved the status of 'classic avant-garde.'"

Much of Crumb's music is written for unusual instrumentation‹pianists reach into the piano to pluck the strings, for example‹and calls for such idiosyncratic touches as lighting of a certain color or shouts from the performer. But he has recently inched his way toward mainstream acceptance, winning a Grammy Award in 2001 and being named Composer of the Year by Musical America in 2003. This year, he has been the subject of several tributes, including one in his hometown of Charleston, West Virginia.