The idea behind the ''Classical Piano Sonatas'' of the preclassical and classical eras is to help the pianist find his way more easily within the profusion of literature in this genre, the most important one within the classical piano repertoire. Carl Philipp Emanuel Bach exemplifies the development which then leads to two charming Haydn sonatas and three elegant ones by Mozart (including the famous ''Sonate facile'' in C major) to the easier piano sonatas of Beethoven and two graceful Haydn sonatas.