It is now regarded as a proven fact that J. S. Bach derived two works from a trio sonata which was most likely in the key of B flat major: the well-known organ Trio Sonata No. 1 in E flat major BWV 525 and the slow middle move-ment of the incomplete Flute Sonata in A major BWV 1032. In his reconstruction, Klaus Hofmann comes as close as possible to the presumably lost original version. While the melody instruments - the range suggests an alto recorder and oboe - were adapted practically without change, the bass part underwent considerable alterations. An organ pedal part simply is not a continuo line. However, Hofmann found a stylistically and idiomatically compelling solution to this dilemma.