Complex sentence: The Prelude in E minor, BWV 855a is a piece for keyboard (harpsichord) composed by by Johann Sebastian Bach that features as No.18 ("Praeludium 5") in the Klavierbüchlein für Wilhelm Friedemann Bach.
Split into simpler sentences: The Prelude in E minor, BWV 855a is a piece for keyboard (harpsichord) composed by Johann Sebastian Bach. It features as No.18 ("Praeludium 5") in the Klavierbüchlein für Wilhelm Friedemann Bach.