Works for piano and string instruments have always been written because of some specific impulse or occasion and with specific performers in mind. Mature in respect of compositional technique, Chopin's chamber compositions belong to the stock concert repertory (especially the ''Trio'' and the ''Sonata''). The ''Complete Works'' is the best known and most popular series of editions of Fryderk Chopin's works, prepared by Ignacy Jan Paderewski, Ludwik Bronarski and Józef Turczynski. The aim of the editorial committee was as faithful a rendition of the composer's intention as possible by firmly basing the publication on manuscripts, copies approved by Chopin himself as well as first editions. The whole consists of 21 volumes.