Beethoven's Piano Sonata No. 14 in C? minor 'Quasi una fantasia', Op. 27, No. 2, popularly known as the Moonlight Sonata was completed in 1801 and dedicated in 1802 to his pupil, Countess Giulietta Guicciardi. This edition of the popular work is based on the thorough review of the first editions of op. 27, comparisons with its follow-up editions, and Beethoven's original manuscript.