Toccata & Fugue in D minor (BWV.565) by Johann Sebastian Bach (1685-1750) is one of the most famous organ-works and is very popular in the world. Peter Williams, musicologist, hypothesized that the piece was originally written for solo violin. Several re-arrangements from organ to violin have been done according his hypothesis. As can been listen these re-arrangements, this great music is also suitable for string instruments. This arrangement is for string quartet. Compared with solo violin playing, the difficulties in playing are greatly reduced by collaboration. However, there appears different difficulty in the quartet version. Sometimes, it is much easier to play by one person than by multiple persons. In the latter case, exact synchronizing between multiple players is necessary and is sometimes very difficult. In this arrangement, a lot of efforts have been done to reduce this kind of difficulty. Many cue-notes deployed in the part-scores will also help co-operating.