The fifth volume of the Drinov Collection is a compilation of articles from three international conferences held at V. N. Karazin Kharkiv National University in 2009-2010: "The Proto-Bulgarians in the Ethno-Social and Political Structures of the Middle Ages," "Homo bizantinus: Faith between Politics and Economics," "Homo bizantinus: Between Ideas and Images," and "The Russo-Turkish War of 1828-1829 and the Balkans." The following sections are presented separately: "Sources and Source Studies," "Reviews," "Anniversaries," and "Scientific Life."