This index originated as a card file maintained at the Library from 1942 to 1992. The card file was then closed, and information on ownership/provenance was entered only into the records in HOLLIS. As older records are updated in HOLLIS (Harvard's online catalog), provenance information is added, resulting in some overlap of ownership information in this file and in HOLLIS.
The card file consists of both typed and handwritten cards. The handwritten cards are often difficult to read, and errors of transcription are undoubtedly present.
From the guide to the Houghton Library printed book provenance file, L-Q., (Houghton Library, Harvard College Library, Harvard University)