The Twenty Etudes for Piano were composed during the years from 1991 to 2012. Their final configuration into Book 1 and Book 2 was determined by the music itself in the course of its composition. Taken together, they suggest a real trajectory that includes a broad range of music and technical ideas. In the end, the Etudes are meant to be appreciated not only by the general listener, but especially by those who have the ability and patience to learn, play and perform the music themselves. -Philip Glass.