Stanford's Copyright Renewal Database compiles all US Class A (book) renewal registrations for works published between 1923 and 1963. These renewals were received by the US Copyright Office between 1950 and 1993.

Copyright status of works published in the US between 1923 and 1963 is of particular interest, as it is dependent on whether the original copyright was renewed. The Copyright Office has never made available in machine-readable form the renewals it received between 1950 and 1977, which would generally cover renewals for books published between 1923 and 1950, and this has made it difficult for libraries and archives to determine which books are in the public domain.

Building on work done by Project Gutenberg to transcribe the 1950-1977 renewals, and on early conversion efforts by Michael Lesk, we have converted the published renewal announcements to machine-readable form, and combined them with the renewals for later years made available on the Copyright Office's website. Note that this database covers only renewals, not original registrations, and is limited to books (Class A registrations) published in the US. Note that the Catalog of Copyright Entries, and therefore this database, does not include entries for assignments, and so cannot be used for searches involving the ownership of rights. Please also note that copyrights restored under Section 104(a) of the copyright act are not represented in this database.

Stanford has performed two rounds of testing in order to assess the accuracy of this database. In each round, we pulled a minimum of 500 book titles published in the US between 1923 and 1963 from the Stanford library catalog. The works were checked manually in the CCE, and, in the first round, a subset of 100 records was also sent to the Copyright Office to be checked by their in-house staff. Each of these items was then separately searched by project staff in the Copyright Renewals Database. In each round, the error rate for the database was found to be less than 1%, although in practice there is significant opportunity for user error or other problems in searching. Details of these issues can be found in Stanford's final report to Hewlett on the project ( PDF), and in the two search results sets ( Search Set #1, Search Set #2).

The full data set for the Copyright Renewals Database is available for download (zip file, 12.8 MB). Stanford welcomes reuse of the data in other systems and search tools.

We welcome and encourage comments on the database. Please send comments to Mimi Calter at mcalter@stanford.edu.