The Nixon Presidential Returned Materials Collection: White House Special Files: Contested Files, consists of documents defined by the President Materials Review Board as private/personal and private/political. These materials were returned to the estate of Richard Nixon in 1996. In July 2007, the Richard Nixon Foundation deeded these materials to the National Archives and Records Administration, and they were made available for research on July 11, 2007. They were made available online on October 20, 2015.
The Finding Aid for these materials describes their provenance in greater detail.
The online User Guide explains how to navigate the digitized materials.
The Contested Index consists of searchable entries for each document scanned.