The author tries to answer the question whether the relatively abundant collection of the 15th century books from the Cyril Belozersky Monastery that are available to us reflects the true significance that this collection enjoyed during the first century of the existence of the St. Cyril Monastery. The reflection in the St. Cyril Monastery manuscripts of the South Slavic influence specific for the epoch and the connection of these manuscripts with the book culture of Moscow and the Trinity-Sergius Monastery (together with the absence of any traces of the Novgorod book culture) are taken as the marking signs of the manuscripts' status. Further, the author dwells on the most difficult and most controversial aspects in the history of the 15th century manuscripts from the Cyril Belozersky Monastery. He discusses the impact on this history of the most famous inhabitants and guests of the Monastery who have been living there in the 15th century, among others Cyril Belozersky, Martinian Belozersky, Oleshko Palkin, Pakhomiy Logofet, monk Euphrosyn, etc.
