The review is devoted to the monograph of the Slovak professor P. Žigo Evolution of Noun Declension in the Slavic Languages. The author appreciates the monograph and considers it as theoretical breakthrough in historical and areal linguistics, as it offers new methodology of the way we read and interpret the linguistic maps of Slavic Linguistic Atlas. The Monograph based on the unique materials of the Slavic Linguistic Atlas, free from previous atomicity and arbitrariness in linguistic research, largely clarifi es the complex picture of connections and relations of the Slavic languages, which have changed often in their long history.