The Prelude in B minor (J. S. Bach, arranged Siloti) is an arrangement for piano by Alexander Siloti of the Prelude in E minor BWV 855a by Johann Sebastian Bach from his Klavierbüchlein für Wilhelm Friedemann Bach. Bach reused the piece (in a slightly different form) as the tenth prelude in the first volume of The Well-Tempered Clavier.
This transcription has been described as "perhaps Siloti's most tender and perfect" composition.[1] It transposes Bach's original down from the original E minor into B minor, and the steady sixteenth note figuration that was originally given by Bach to the left hand is changed to the right hand. Siloti also adds a repeat of the entire work, in order to allow for a change of voicing where the melody in the left hand is emphasized.[1] The chords in the left hand are arpeggiated; however according to Siloti's daughter Kyriena (to whom the work was dedicated [1]), he would omit the arpeggiation on the first pass and restore it on the repeat in order to heighten the effect of the left-hand melody.[1] It has been performed by many pianists, most famously Emil Gilels.[1]