The letters were originally bound in twenty-three volumes. In the earlier volumes they were numbered, in the later, foliated. On the whole they were arranged in order of date, but many were misplaced. Inside the back cover of several volumes were notes of John Gibson Lockhart, apparently made when he was writing the ‘Life’. Some of these give a reference to the number or folio of the letter.

The contents of each original volume have now been re-bound in two volumes. Misplaced letters have in some but not all cases been moved to the appropriate place; the contents of the original volume xxiii have been extensively re-arranged. John Gibson Lockhart's notes will be found at the end of the second of the two volumes into which each original volume has been divided.