Manuscript catalogs connect advanced history researchers with important primary documents housed in obscure and not-so-obscure collections all over the country. Generations of scholars have turned to the National Union Catalog of Manuscript Collections (NUCMC) to track down collections critical to historical research. ArchiveGrid is a new database from the Research Libraries Group (RLG) that also allows researchers to locate relevant manuscript collections. “Thousands of libraries, museums, and archives have contributed nearly a million collection descriptions to ArchiveGrid. Researchers searching ArchiveGrid can learn about the many items in each of these collections, contact archives to arrange a visit to examine materials, and order copies” (ArchiveGrid). RLG is providing free access to ArchiveGrid through May 31, 2006. After this date ArchiveGrid will remain free if RLG receives additional funding to continue the project. If funds are not found, ArchiveGrid will be made available to institutions as a subscription. All records in the NUCMC catalog are said to be available in ArchiveGrid. Given that ArchiveGrid is a brand new resource, researchers should consult both databases for the sake of completeness. Graduate students and senior scholars should cross-check online search results against the print version of NUCMC. —David C. Murray Postscript: History researchers might also wish to consult Ready, Net, Go!, an index/guide to archival research on the web created by the Special Collections Division of the Howard-Tilton Memorial Library, Tulane University.