Prelude (Toccata) and Fugue in (C or) E major, BWV 566 is an organ work written by Johann Sebastian Bach in 1708. It comprises four sections and is an early[1]work of Bach's.
Its form resembles the Preludes and Fugues of Buxtehude. The first section alternates manual or pedal cadenzas with dense suspended chords. The second is a charming fughetta with much repetition following the circle of fifths. The third section is a brief flourish for manuals ends with an even briefer pedal cadenza punctuated with 9-voice chords. The fourth section is in 3/4 time, and is a second fuga with a rhythmic subject resembling the thema of the first fughetta.
Bach also wrote a transposed version of this in C major, to play on organs tuned in meantone where E major would sound discordant due to the organ's temperament. Various recordings of the C major version exist mainly on historic instruments, for example Ton Koopman's recording on the Schnitger organ in Hamburg's Jacobikirche, and Marie-Claire Alain's recording on the Silbermann organ at Freiberg Cathedral. Both have a high pitch leaving the "concert" pitch up to a tone higher than modern pitch, where the temperament is significantly unequal to merit playing it away from E major. Modern organs or those tuned to a more equal temperament do not have this need.