The form and function of popular encyclopedias went through very considerable changes in the 19th century. The study outlines the emergence of the general reference work as a genre in its own right and its differentiation into various types (Konversationslexikon, popular encyclopedia, specialized dictionary). The comparison of encyclopedia production in Germany and Britain, which is notable for a variety of reciprocal reception processes, clearly shows up the frequently non-synchronic stages in the process of change undergone by the genre, e.g. the increasing significance of these works as sources of information and reference as opposed to an educational tool.