Дисертація присвячена актуальній для української біографістики темі: комплексному висвітленню життєвого шляху і дослідженню наукової, архівної та громадської діяльності Олени Апанович. Дослідження дало змогу виділити основні етапи життя, прослідкувати еволюцію світогляду, уточнити наявну в українській історіографії періодизацію наукової діяльності О. Апанович. Вона зробила вагомий внесок в історію та джерелознавство українського козацтва, вивчення козацького літописання та рукописної книги, дослідження біографії В.І Вернадського, відродила маргіналістику. Працюючи в академічному Інституті історії України, вчена стала важливим суб'єктом трансформацій в історичній науці і громадському житті України другої половини ХХ ст. Її наукова та громадська праця з історії і пам'яток українського козацтва давала поштовх до зростання національної самосвідомості в Україні. Про це свідчить її участь у проєкті заповідника на Хортиці. Вивчення архівної діяльності Олени Апанович показало, що вона провадила значну роботу з упорядкування та публікації документальних фондів ЦДІА УРСР та відділу рукописів ЦНБ АН УРСР. Була активною і в жіночому русі у 1990 рр. Плідною була праця О. Апанович як керівника секції історичних пам'яток Київської організації УТОПІК.^UThe dissertation is devoted to an important for Ukrainian bibliography topic – systematic analysis of the life, scientific endeavours, archivistics and civil activities of Olena Apanovych. The analysis allowed to distinguish the life stages, life outlook evolution, and to clarify an available in Ukrainian historiography periodization of Olena Apanovych's activities.There were a couple of scientific research flows of Olena Apanovych revealed:1) the history of Ukrainian cossacks and early-new history; 2) archeography and source studies; 3) cossacks manuscripts and Ukrainian manuscripts history; 4) bibliography;5) philosophical history and historiography. Among those flows, the most famous and productive was the one on cossacks. However, it was not the only one founded the authority of the scientist. Additional ones were analysis of bibliography and scientific activities of V. Vernadskoho, who actually revealed to the scientific public by her. The scientist recreated the analysis of manuscripts and marginalistics.The research established that for a long working of time in the Institute of History AN USSR earned a respect among historians and civil society. She became an important figure in Ukrainian humanitarian research of 1960th. She was a member of non- conformists group of scientists and thus forced to resign from the Institute of History. As a restoration of justice, she employed back to the institution in 1995. However, due to the respected age and illnesses she could not proceed with an active scientific and managerial work and concentrated her efforts on cossacks research.The sources base allowed analyzing the previously unrevealed archive activity of Olena Apanovych during 1944–1950th in TsDIA URSR. It was summarized that the scientist not only conducted research on cossacks but also conducted a significant work on systematization and analysis of documental funds of previous periods. Special contribution made to manuscripts department of TsNB AN URSR. She systematized significant amount of archives and revealed the two new scientific topics: Ukrainian manuscript and bibliographical analysis of Volodymyr Vernadskyy activities. Especially important were the analysis of the academic's diary and other documents of the first president of UAN as well as preparation of scientific analyses and monographies on different related to V.I. Vernadskyy matters.A very important aspect of civil activities of Olena Apanovych is her role in equality movement. Despite Ukrainian Women Association named after Olena Teliha was already working towards national and cultural upheaval of Ukraine, the famous historian was an active participant and promoter of the process. That is why she appointed as an Honourable Member of the Association.The paper also analyses not a well-known activity of Olena Аpanovych as a director of the historical heritage department of the Kyiv Branch of the Association of History and Culture. In 1966, she was a founder of the Association, a board member and a director of the historical heritage department. During her term, the association becamethe leading organization in Kyiv. She was coordinating famous scientists and historical heritage preservers. Among other projects, she leaded Pechersk fortification preservation, which is now a part of Kyiv-Mohyla Academy, Golden Gates, Florovsky monastery and other historical sites. She also contributed to register of Kyiv sites foundation, when the first Podil inventorization has conducted.It was proved that the main topic of Olena Apanovych's research was not only cossacks but also preservation and popularization of cossacks' heritage. The scientist was among ideologists of cossacks heritage preservations both movable and immovable. She approached it systematically and tried to rise national self-identification of Ukrainians. This includes historical heritage of cossacks preservation, heritage register, and educational events. Importantly, the main project of Olena Apanovych in cossacks heritage preservation, where she was the main leader and concept former, which was the historical and cultural center on Khortytsia. She saw it as a future pantheon of сossacks' fame. Despite some of her ideas (on reburial of cossacks' leaders in Khortytsia) were not supported by the party leaders, anyway she engaged a great quantity of scientists and civil society to heritage popularization and caused significant mind shift in society as a whole. Due to these factors, management of the Soviets was slowing the project down. In times of reconstruction when she cloud realize the projects again, she leaded two expeditions: “Zaporizka Sich: destructed and preserved” in 1989 and 1990. As it predicted this could draw attention not only by scientific centers but it could activate local civil society to cultural heritage preservation activities.