This paper takes a critical approach to understanding a dictionary as a neutral source of knowledge. A dictionary is studied as a collection of traces left in it by its authors and the society in which the dictionary is created. The main aim of this study is to discover how the monolingual explanatory Czech and Croatian dictionaries reflect differences in social organisation of the two former socialist republics: Yugoslavia and Czechoslovakia. A sociolinguistic comparative analysis of the forewords of Czech and Croatian dictionaries published during the socialist period was carried out. Special attention was paid to the parts of the text referring to the social reality and circumstances related to the creation of each dictionary. The main hypothesis was that in Czech dictionaries more attention had been dedicated to socialism and its relations to lexicography, whereas in Croatian dictionaries the topic of language as an index of national identity had prevailed. The analysis reveals differences in the status of lexicography in the two societies and describes extralinguistic (economic, ideological, political) impacts on lexicography. The results confirm the hypothesis that the topic of socialism is prevalent in Czech dictionaries, as opposed to the subject of nation being more present in Croatian dictionaries.