The cumulative index is the most up-to-date version, providing references to specific pages in the published volumes and superseding the indexes in the printed volumes. The abbreviation "TJ" stands for Thomas Jefferson. Copies of the published volumes are available at a library near you , or may be...
This is the current index for the Retirements Series. I've spent a lot of time working with this thing. I never gave much thought to indexes, until I got to know one personally.