J. S. Bach's three gamba sonatas belong among the core repertoire of this low string instrument. They hark back to other works of his that were originally for different performing forces. What they all share is a strict three-part texture (gamba and two-voice keyboard). Our viola arrangement reflects Bach's own arranging practice. Only in a few passages does the original gamba part descend below the viola's tonal range, and these can easily be resolved by moving the melody line to a higher octave.