This paper deals with J.B. Rudnyckyj (1910-1995), a leading Ukrainian émigré scholar of the Cold War period, and his manifold contributions to library science in Canada and the West in general. Although he was a philologist and lexicographer by training and profession, Rudnyckyj took a keen interest in all Ukrainian books and libraries to which he had access during this period. From his very immigration to Canada in 1949, he traveled extensively in this country, in the USA, and in Western Europe. Everywhere he went, he investigated local private Ukrainian, public, and academic libraries, museums, and cultural centres, met with resident scholars, both émigré and Western, and wrote about them in his voluminous publications. These included both travelogues with a strong cultural bent and also more formal library descriptions. For two decades he also compiled extensive yearly bibliographies of Slavic publications in Canada. Rudnyckyj's motivation, it seems, was a desire to document and preserve the Ukrainian cultural heritage which he thought was under threat in his ancestral European homeland. Today, all this material forms a valuable resource for the history of Slavic studies in Canada during the time of the "Long Cold War" (1945-1991). It also says much about Ukrainian culture in North America in general during this period. [ABSTRACT FROM AUTHOR]