Archives and manuscripts

Witkiewicz, Stanisław Ignacy, 1885-1939. 2 postcards (illustrated autograph manuscript) to Zofia Mikucka, 1928. Postcard postmarked "14.V.28.11". From collection: Witkiewicz, Stanisław Ignacy, 1885-1939. Correspondence. Papers, 1928-1936 (bulk), 1928-1971 (inclusive)

Soviet history: archival resources at Harvard university library and archives
A LibGuide to Harvard-owned archival materials documenting the history of the Soviet Union. It is arranged chronologically and by topic/provenance. 

Archival Sources for Soviet History at Harvard Libraries & Depositories
A guide to Harvard's archival collections for Soviet history compiled by Matthew Lenoe (under review)

A Guide to Ukrainian Special Collections at Harvard University
Fully digitized guide to collections of Ucrainica at the Harvard University Libraries compiled by Ksenya Kiebuzinki and published in Harvard Library Bulletin, 2007 Fall-Winter, Vol.18(3-4), pp.i-xi, 1-107.

Archives and Ephemera tabs in the Selected E-Resources in Slavic Studies section of this guide
A list of primary sources available in e-format to Harvard researchers, with hyperlinks

HOLLIS for Archival Discovery
A dedicated section of Harvard Library's catalog that provides electronic access to information about collection guides, finding aids, and inventories to locate unique materials in Harvard's special collections and archives.

How to Use Harvard Library's Special Collections and Archives
The Harvard Library page providing guidance in finding and accessing rare and unique materials across Harvard repositories.

Archives and Manuscripts section of Harvard Library's Library Research Guide for History

See also:

The Russian Empire and Soviet Union : A Guide to Manuscripts and Archival Materials in the United States
A searchable online guide created by a team of Research Associates of the Kennan Institute for Advanced Russian Studies with the support from the Research Division of the United States Office of Education and from the National Endowment for the Humanities.