In 1934, in the publishing concern of I. Tyktor “Ukrainian Press”, the editorial board of the biweekly “Nash Lemko” was formed, the first editor of which was Yulian Tarnovych, who later founded the “Library of Lemkivshchyna” publishing seria, which published and distributed books on Lemki subjects, in which the overarching idea was the idea of historical and mental unity of the Lemki people with Ukrainians from other regions, and hence the popularization of the Lemko region and the centuries-old cultural heritage of its inhabitants as a component of Ukraine and the Ukrainian people. In the article, for the first time, all editions of the book seria “Library of Lemkivshchyna” of the magazine “Nash Lemko” 1936–1939 edited by Yu. Tarnovych were investigated, and the exact authorship of individual numbers stored in the departments of Ukrainian studies and rare books of the Vasyl Stefanyk National Scientific Library of Ukraine in Lviv and in the Scientific Library of LNU named after I. Franko, the factual content and thematic palette of the book editions of the seria were analyzed, their relevance at the time and today was proven, reviews and reviews of the book products of the seria were introduced into scientific circulation. Among the analyzed publications are books by eight authors, cultural figures of the Lemko region (Yu. Tarnovych under his own name and pseudonym Vsevolod Yaroslavych, R. Antonovych, I. Shevchyk-Lukavychenko, F. Kokovsky, V. Klish, O. Mysevych, I. Bugera, V. Hylak under a pseudonym Yeronim Anonim). The analysis of the factual content and subject matter of the book editions of the entire seria showed that, promoting the idea of Ukrainian national unity, they contributed to the formation of the Lemks’ understanding of the uniqueness of their traditional material and spiritual culture, national identity, revitalization of the social life of the region, were an important factor in the patriotic education of young people, introduced wide circles of the Ukrainian public of Galicia to the life and spiritual heritage of the westernmost branch of the Ukrainian people. Today, they are a valuable source not only for studying the publishing culture of the past, but also for the history of the development of Ukrainian ethnic identity in the Lemko lands.