This collection contains personal and professional materials of Mykola Duplak. Among Duplak’s personal materials are correspondence, photographs, an address book, and certificates. Duplak’s professional life is represented by materials from his time as an executive of the World Lemko Federation and founder and curator of the Ukrainian Lemko Museum, materials related to Narodna Volya (including correspondence from his time as editor, minutes, notes, membership lists, and financial records), correspondence from his work with the Research Society of Ukrainian Terminology, and materials from the Ukrainian Fraternal Association, including correspondence, membership lists, notes, and minutes.

The collection contains writings by others, including books (some signed and annotated), magazines, and newspaper clippings. It also contains subject files on a variety of topics, including the Demjanjuk case, the Shevchenko Centennial, Children's Library play booklets ("Children's Theater"), Nicholas Biloskirka, the Hetman regime, and dictionary materials. There are also Vasyl' Verhun's materials, including his writings and personal documents.

Audiovisual and digital materials include a DVD interview with Mykola (Nicholas) and Helen Duplak, diskettes related to the 24th Convention of the Ukrainian Fraternal Association, and compact discs, including discs such as "Kul'tura i Mova" and "Osnovni Pytannia Ukrains'koi Tserkvy i Narodu."