18 October 2014
Hundreds of the record groups at NARA have inventories to help us identify various series of original material within that record group. If the inventory was considered complete and final at the time of preparation, it was labeled "inventory" and published. If the inventory was considered tentative, it was labeled "preliminary inventory" (PI in everyday lingo) and was maintained in-house. Both series are numbered separately, with overlapping numbers.
Copies of these guides have been distributed to libraries and individuals upon demand. Printed copies are available on site at NARA-D.C. and (randomly) in NARA branches and government depository and repository libraries across the United States. Many have been digitized by Google Books or Archives.org. All the inventories and preliminary inventories produced between 1936 and 1968 are available on microfilm.1 Some are being reproduced commercially.
As yesteryear's people used to say: Where there's a will there's a way. If we're serious about NARA research, we can find a way to acquire the guides we need to make us proficient researchers. EE's Chapter 11 "Federal Goverment Records" and 13, "Publications: Legal Works & Government Documents" (pp. 725-76) will also introduce you to many more national-level research materials, along with examples of how to cite them.
1. Publications of the National Archives, 1935—, microfilm publication M248, 52 rolls (1956; updated, Washington, D.C.: National Archives & Records Service, 2001). Also see National Archives and Records Administration, Select Publications, General Leaflet no. 3 (http://www.archives.gov/publications/general-info-leaflets/3-publications.pdf).