Ludwig Van Beethoven: Piano Sonata No.13 In E Flat Op.27 No.1 "Quasi Fantasia" (Schirmer Performance Edition) Beethoven's Piano Sonata No.13 In E Flat Op.27 No.1 "Quasi Fantasia" is now available as an individual edition with a companion CD, edited and recorded by noted Beethoven scholar, Robert Taub.