The original piece is written for piano. This and other arrangements of the same piece have been elaborated for the following main reasons: 1) to introduce the young pianist to the original piece via simpler version(s) of it (quicker and easier to learn); 2) to better appreciate the accurate polyphonic writing of the composer (whereas the young pianist�s vision of a piece is often exclusively "vertical" or harmonic); 3) to approach the original piece through an ensemble version (which forces a rigorous execution); 4) to spread among instruments different from the piano the knowledge of absolute masterpieces of the evergreen music, originally written for piano but - I think - not seldom conceived for groups of other instruments.