Footnotes have been an integral part of the HBBW since its inception. Despite guidelines for the editing process in the first volume's introduction, there was no specific classification or usage instructions for footnotes. In total, the editors have annotated 3,113 letters with 79,573 footnotes, of which 65,855 (82.76%) are <hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic">factual footnotes</hi>.