Russian Heroic Epic

The first book in which philologist and folklorist V. Y. Propp examines the Russian heroic epic as part of Russian culture, Russian history, and Russian reality. What are the differences between epic, myth, fairy tale, bylina, and novel? What motives lie behind the actions of well-known heroes from childhood? What meanings do the unadapted plots of bylinas carry - harsh, dramatic, poetic, full of symbolism and heroism?