The Cello Sonata is a late work by the French composer Claude Debussy. It was the first of a planned series of 'Six sonates pour divers instruments', however Debussy only completed two others, the sonata for violin and the sonata for flute, viola and harp. The sonata for cello and piano was written in 1915, and is notable for its brevity, most performances not exceeding 11 minutes. It is a staple of the modern cello repertoire and is commonly regarded as one of the finest masterpieces written for the instrument. The two final movements are joined by an attacca. Instead of sonata form, Debussy structures the piece in the style of the eighteenth-century monothematic sonata, and was particularly influenced by the music of François Couperin. The piece makes use of modes and whole-tone and pentatonic scales, as is typical of Debussy's style. It also utilises many types of extended cello technique, including left-hand pizzicato, spiccato and flautando bowing, false harmonics and portamenti. Not surprisingly, the piece is considered technically demanding.