This Fugue, from Bach's 48 Preludes and Fugues (known as The Well Tempered Clavier), is in 4 parts. Generally speaking the top 2 parts are notated for the right hand and the bottom two by the left hand, but there are places in the score where it is much easier to play the middle parts with the other hand. This fugue should be played slowly and smoothly with appropriate slurring to separate the repeated quavers. Bach's Preludes and Fugues come in matched pairs in the same key, and are usually (though not always) played as a pair in the order Prelude first and then Fugure. Here is the corresponding Prelude for this Fugue. The complete collection of Bach's 48 Preludes and Fugues are available as follows: Book 1 and Book 2 from Sheet Music Plus.