Any consideration of Bach manuscripts must begin with the work of two scholars: Georg von Dadelsen (1918-2007), who broke new ground in Bach scholarship by dating Bach’s manuscripts through analysis of the handwriting of Bach and his copyists;2 and Alfred Dürr (1918-2011), who was able to establish a new chronology of Bach’s vocal works composed in Leipzig by studying watermarks and identifying the individual copyists.3 For those who accepted the validity of the old chronology proposed by Philipp Spitta (1841-94) in the late nineteenth century, which until then had been considered unassailable, it was an earth-shattering realization that the foundation of their scholarship had been removed. A half-century has passed, and although a number of refinements have been made to the findings of Dadelsen and Dürr (and others), their theories and methodologies have remained broadly unchallenged. There is, however, every reason to believe that future generations will develop new techniques and methodologies that will re-evaluate existing evidence and discover new perspectives in Bach research.