My comments:

This series by Max Farrand, originally published in 1911 as a 3-volume set, is considered by scholars as the definitive record of the Constitutional Convention. It includes James Madison‘s Notes, the most complete set of any delegate, which have been published as a standalone work. Farrand published a 4th volume in 1937 to add supplemental material found after his first publication. James H. Hutson published a Supplement to Farrand’s work in 1987, containing more related material found after Farrand’s publication. The latter two, both still under copyright, are a little harder to find, but I included them below as part of this series. The first three volumes, not under copyright, are widely available online, also as shown below.