[This note covers all of the Patent Application Files for Part III.]

These files contain patent applications and related drawings, along with correspondence between Edison's attorneys and the U.S. Patent Office. Many of the applications pertain to improvements in Edison's phonograph. There is also material relating to electric lighting and power, ore milling, motion pictures, and various other technologies.

Another set of application files for Edison's U.S. patents can be found in the National Archives (Record Group 241, Records of the Patent Office). The National Archives set is nearly complete for this period and is available on microfilm. For that reason, the formal specifications and the correspondence between Edison's attorneys and the Patent Office have not been selected in the case files for the successful applications in the Edison National Historical Park's collection. The selected material from these files consists primarily of notes, drawings, and draft specifications by Edison, along with occasional correspondence to or from Edison, his associates, and his companies. The case files for Edison's abandoned or forfeited applications have been selected in their entirety except for duplicates, printed patents by Edison and other inventors, and other printed material.

The draft notes and drawings in the Patent Series bear a close relationship to the notes and drawings in the Notebook Series, many of which carry inscriptions indicating that they were used in the preparation of caveats or patent applications.

The patent application files are arranged in chronological order according to execution date, the date on which the formal application was signed and witnessed. For Edison drafts, the dates appearing on the documents are generally earlier than the formal execution date.