The edition is based on Volume 14 of the complete edition of the Bach-Gesellschaft (Breitkopf and Härtel, Leipzig, 1864) as well as on Hermann Keller's new Urtext-edition (Edition Peters, Leipzig, 1963). In shaping the text of the publication we also studied the major Urtext editions in general use today. The text variants of an Urtext validity which by and large equal the main text, are given in ossia. The editor's addenda are put in square brackets, or in the case of ligatures, are marked with broken lines.