"The Moonlight Sonata," officially known as Piano Sonata No. 14 in C-sharp minor, Op. 27, No. 2, is a famous piano composition by Ludwig van Beethoven. Completed in 1801, it is renowned for its expressive and melancholic first movement, which evokes a serene, moonlit night. The piece is structured in three movements, with the first being the most well-known. The sonata was originally titled Sonata quasi una fantasia and reflects Beethoven's innovative approach to piano music. The second movement offers a contrasting, lively character, while the final movement is more dramatic and intense. This work remains a staple in the classical piano repertoire.