Claude Debussy was a French composer from the late 19th and early 20th centuries who wrote a famous piece called Clair de Lune. His music is often compared to Impressionism in art. The preludes in book two are twelve works of very different styles, composed from 1910 to 1913. Compared with book one, the second book of the prelude reflects Debussy's musical style's transformation. Melody innovation, bi-tonality, overlapped chord, and a small amount of compound rhythm, or polyrhythm. The titles are still placed at the end by the composer in book two, like what he did in book one. In notation, Debussy often uses three-line staff in book two, reflecting his extensive use of the entire piano keyboard. The themes of these preludes are also diverse. For example, there are depictions of landscapes, ancient cultures, exotic customs, humorous scenes, or even supernatural fairies. The "24 Piano Preludes" is one of Debussy's piano masterpieces. A prelude is a mini-fantasy form of Piano. In the 15th century, the prelude's role was to prepare or test for the audition before the performance, especially for keyboard instruments. It was only formed after the 17th century. Debussy's unique understanding of this musical style has been demonstrated in his "24 Piano Preludes".