The book is the first dictionary of proper names in the texts of Belarusian, Russian and Ukrainian riddles in East Slavic folklore and ethnolinguistics. The material collected and systematized by the author significantly complements our knowledge of the East Slavic picture of the world, as well as the typology of riddles and related genres. The first part of the book contains information about which proper names are used to encrypt a particular phenomenon. The second part is devoted to those cases when proper names are not used for encryption.