Piano Sonata No. 27 in E minor, Op. 90, is a composition by Ludwig van Beethoven completed in 1814. This sonata consists of two contrasting movements, showcasing Beethoven's innovative style and emotional depth. The first movement is marked by its dramatic intensity, while the second offers a more lyrical and reflective character. The sonata is notable for its use of complex harmonies and intricate melodies, reflecting Beethoven's transition into his late period. It is often performed in concert settings and is appreciated for its expressive qualities, making it a significant work in the piano repertoire.