This is one of Bartók's most famous series of piano pieces, whose fame is probably greater than either its popularity with pianists, or the frequency with which it occurs on concert programmes. When it was written [in 1908] it triggered sensation and scandal in musical circles. The series as a whole (its Hungarian title was originally "14 Piano Pieces", Bartók later converting to the use of the word bagatelle in Hungarian too) is not a true cyclic composition that can only be played in its entirety and with movements in the original order, but rather a more loosely ordered collection, an anthology. Some of the pieces belong together. But the varied succession of tempos and characters, the 'Gradus ad Parnassum' principle, generally proceeding from the easier towards the technically or musically more difficult, could also be a reason for the volume's ordering.