From Bach's Well Tempered Clavier, or The 48 Preludes and Fugues, this prelude can be played by anyone of moderate ability. Use a light touch and try to make the right hand triplets as even as possible, while varying the phrasing in the left hand. It is in the key of D minor, and along with its corresponding fugue in the same key, it is catalogued as BWV 851.
Although there are some easier preludes and fugues in the set, much of Bach's Well-Tempered Clavier is quite challenging to play. However the complete set has for a long time been considered a must for any serious student of piano. Some other preludes and fugues from the set are available on mfiles if you check the Bach page or Classical Sheet Music page. If you have aspirations to be a good classical pianist then we recommend getting the complete Well-Tempered Clavier which comes in two books. Here are links on "sheet music plus" to Book 1 and Book 2 of the Well-Tempered Clavier.
The audio controls below allow you to play the mp3 version of Bach's Prelude no.6 in D minor from Book 1 or you can download the MP3 file. You can also download the midi version of Bach's Prelude no.6 in D minor from Book 1 or alternatively edit/play the midi file.
The image below is the first page of the sheet music, and here you can download the full sheet music for Bach's Prelude No.6 from book 1 in PDF format.