Johann Sebastian Bach's chamber music was in constant transition. His few surviving trio sonatas, for the traditional combination of two melody instruments and continuo, likely date from his years in Weimar and Kothen. Bach revisited some of these works in Leipzig, reworking them for concerts at Zimmerman's coffee house into sonatas for a melody instrument with harpsichord obbligato. Unfortunately, few of these manuscripts survive, leaving us with only later arrangements as rough clues to their original form and instrumentation. Prominent Bach scholars agree that Bach, just as Handel and Telemann, must have made a major contribution to the main genre of 18th century chamber music. In view of this evaluation, there is a particularly unfortunate gap in the catalogue of the Thomaskantor's works. Our program was conceived as an approximation of some of these lost trio sonatas.