Musica Ricercata of 1951-53 is a collection of 11 piano pieces which even with their traditional character went beyond what was considered appropriate for performance in Hungary in the early 1950s. The tenth piece, e.g., was considered too "decadent" because of the abundance of minor seconds. The short "Capriccios" and "Invention", written in 1947-48, reveal convincingly the emergence of Ligeti's musical identity. "Monument � Selbstportrait � Bewegung" (three pieces for two pianos) was written in 1976 while Ligeti was working on the opera "Le Grand Macabre". The conception of these three pieces arose from the inherent technical possibilities afforded by the simultaneous playing of the two pianos. Ligeti works here with processes which develop consequently from an initial core to unfurl in great complexity.