The information given in the entries for the period 1940–1946 was obtained from the record books of the Copyright Office, the original applications for the registration of the copyright claims, and the descriptive material deposited with the applications and films at the time of registration. For the period 1947–1949, the information was transcribed (with slight changes in the order of the material, for the sake of consistency) from card copy previously used in the preparation of the semiannual issues of the _Catalog of Copyright Entries, Third Series, Parts 12–13, Motion Pictures_. Beginning with July 1, 1949, the title of Parts 12–13 was changed to _Motion Pictures and Filmstrips_ and filmstrips registered in Class J were listed. These filmstrips, however, have been omitted from the cumulative catalog. The card copy was compared with the record books and the file of original applications to make certain that all works registered during the period were recorded in the catalog. At the same time any errors in the names of the claimants or the dates of publication found in the card copy were corrected. Each entry contains information which describes the film and identifies the copyright claimant, the date of the beginning of the copyright term, and the copyright registration number. The descriptive portion of the entries varies considerably in fullness depending on the information available in the sources used. The entries for unpublished works contain the date or dates of deposit in the Copyright Office of the title, description, and required prints. The entries for published works contain date of publication as given in the application for registration. Deposit of published copies has in every case been made. In each entry the name of the claimant is that given in the application. Information relating to renewal copyrights or to subsequent changes of ownership recorded in the Copyright Office can be ascertained upon request and upon payment to the Register of Copyrights of the fee specified in the law for the conduct of a search of the records. In addition, information relating to renewal copyrights can be secured by referring to the issue of the _Catalog of Copyright Entries_ covering renewal registrations for the particular class of work during the renewal period. The publication of the _Catalog of Copyright Entries_ is authorized by sections 210 and 211 of Title 17 of the _United States Code_. Section 210 provides in part: “The current catalog of copyright entries and the index volumes herein provided for shall be admitted in any court as prima facie evidence of the facts stated therein as regards any copyright registration.”