Case study of OUN military activities theory in the interwar period is complex, multifaceted and requires objective analysis of sources. The greatest interest to the characteristics of the main works of M. Kapustiansky V. Kurmanovich, R. Sushko, on the creation of Ukrainian army and military doctrine were fund of the Central State Archive of higher authorities and management of Ukraine, the State Archive of the L’viv Region. Archive of OUN within Olzhych Foundation in Kiev was useful in the study of correspondence material of E. Konovalets, M. Kapustiansky, M. Stsiborsky and others. Special attention is paid to the analysis of literary memoirs literature, nationalist newspapers and magazines, as well as fundamental monographs and dissertations.
Issue of creation the Ukrainian army always remained actual for the OUN, which stood on the position of Ukrainian statehood. OUN was involving the soldiers, who was the former ruler of the Ukrainian army, to their ranks, by bidding only on the armed liberation of Ukraine. Among those who participated in historical and theoretical researches were leaders of OUN, such as: E. Konovalets, M. Kapustiansky, V. Kurmanovich, R. Sushko, M. Kolodzinskyy, R. Shukhevych, A. Hasyn, Z. Kossak. Their rich experience of the First World War and the liberation fights of 1917–1921, good professional military education became a valuable contribution to the organization and educational activities of OUN during interwar period.
In the works: «Military knowledge», «On the question of Ukrainian military doctrine», «For armed Ukraine», «War and equipment», «Ukrainian Armed Force and Ukrainian national revolution» M. Kapustiansky considered the future of the war and developed tactics and strategy of Ukrainian Nationalists. The main focus of military and historical studies for M. Kapustiansky, were problems of Ukrainian revolution, the history of the armed fight of the Ukrainian people for independence. There are a number of memoirs and analytical works among scientific and historical creative heritage of M. Kapustiansky: «Essays records years 1929–1939», «On my memory screen,» «Remembered». He, as eyewitness of the Ukrainian revolution, described past events at work «Campaign of Ukrainian army on the Kyiv-Odessa in 1919».
General B. Kurmanovich, as experienced soldiers, actively participated in the creation of a textbook on military training for former officers of UHA. Thanks to the efforts Musketeers Communities was published a «Sketch textbook for Ukrainian officers and junior officers» in Canada, with a foreword by General V. Kurmanovich.
Roman Sushko took part in writing a textbook on military training, which is published in Paris. Important and interesting publications are documentary works of R. Sushko in the «Calendars Red Guelder Rose». These works still not lost its scientific and cognitive value.
Creative achievements of OUN military leaders were feature with wide range and depth of thinking, high professionalism. All training and theoretical developments of OUN officers are the source for study of military and historical views on the nationalist organization activities in 1929–1939 years. This heritage can be used in developing process of modern Ukraine state building, reforming the armed forces, and perspective of entering the European structures and NATO.
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