The Addendum to The Collected Letters of Robinson Jeffers, with Selected Letters of Una Jeffers offers a comprehensive survey of the project.
Part 1 lists the public and private repositories where letters are held.
Part 2 provides an inventory of all letters archived in each location.
A merged, chronological list of published and unpublished letters is contained in Part 3.
Letters cited in footnotes, but not otherwise included in the edition, are identified in Part 4.
Letters added after the edition was published are presented in Part 5, along with a list of corrections for all three volumes.