Book 10 of the series "Cyril and Methodius Studies" contains nine philological and historical studies devoted to the work of Cyril and Methodius, Bulgarian literature and poetry from the end of the 9th to the beginning of the 10th century. The volume has been prepared in connection with the 1100th anniversary of the Council of Preslav, an important moment in the cultural history of the Bulgarian people. The focus is primarily on some significant phenomena of Preslav literature from the Golden Age—the volume and characteristic features of unexplored and little-studied Preslav translations from Greek of narrative works (the lives of Paul of Thebes, St. Condrat, Pseudo-Methodius' Revelation), the spread of Bulgarian translations and the principles of Bulgarian writers of that era in Russia, Old Bulgarian writing systems, and the rhythmic structure of Preslav texts. In the book, the reader will find publications of the texts of some Cyril and Methodius sources in 17th-century manuscripts preserved in Polish collections, which have not been studied until now; an attempt to reconstruct Cyril and Methodius' Old Bulgarian text of the Four Gospels; an analysis of the poetic devices in Clement of Ohrid's Words and one of the most controversial passages in the Extensive Life of Constantine-Cyril.