This collection consists of the personal and professional materials of Leonid Sonevyts'kyi, including biographical documents, diaries, appointment books, photographs, correspondence, and receipts, along with copies of and notes for published materials, manuscripts, speeches, articles, scientific reports, and bibliographies. The collection also contains published third party materials, including maps of Ukraine, almanacs, reviews, newspaper clippings, and obituaries. Finally, included are typescripts of Mykola Arkas works.