By Definition, an Encyclopaedia is “A Work that Aims at Giving a comprehensive summary of all branches of knowledge… Encyclopaedias usually consist of articles on separate subjects arranged in dictionary or alphabetical order to facilitate use… .” A more differentiated view is given by the New Encyclopaedia Britannica, which describes encyclopaedias as follows: “Today most people think of an encyclopaedia as a multivolume compendium of all available knowledge, complete with maps and a detailed index, as well as numerous adjuncts such as bibliographies, illustrations, list of abbreviations and foreign expressions, gazetteers, and so on…”

Unlike the Encyclopaedia Americana or the Encyclopaedia Britannica, whose primary goals have been and still are to serve as comprehensive and always up-to-date works of reference of general knowledge, the Encyclopaedia Iranica would fall under the category of specialized encyclopaedias “that have deliberately been planned for a special purpose” or even better: encyclopaedias of countries and regions “dealing with a single country and region.”