Bach's Trio Sonata BWV 1038 for Flute, Violin und Continuo proposes a conundrum. It has survived as a set of parts in Johann Sebastian Bach's hand – yet the source does not give a composer. Thus its authenticity has been called into question time and again. According to the latest research, however, this tone sensitive sonata is presumed to be an original work by Bach. Our editor Peter Wollny, a declared expert, outlines the reasons for this in detail. The violin part is to be played in scordatura according to the source, so we have provided a part in original notation as well as in standard notation for regularly tuned violins.