The basis for this additional volume are the three volumes of the handbooks Dictionaries. An International Encyclopedia of Lexicography (HSK 5.1 to 5.3), published between 1989 and 1991. An updating has been perceived as an important desideratum for a considerable time. In the present Supplementary Volume the premises and subjects of HSK 5.1 to 5.3 are complemented by new articles that take account of the practice-internal and theoretical developments of the last 15 years. Special attention has been given to the following topics: the status and function of lexicographic reference works, the history of lexicography, the theory of lexicography, lexicographic processes, lexicographic training and lexicographic institutions, new metalexicographic methods, electronic and, especially, computer-assisted lexicography.