Stamp dating and dictionary
Collections for historical research deal with the history of postal markings and other aspects of postal practice. Thematic collections may be limited to a specific interest of the collector, for example, the subject of the design; documental collections consist of stamps and postal and other documents that elucidate a certain aspect of philately.
In 1976 it consisted of national societies from 57 countries; since 1929 it has sponsored regular international philatelic exhibitions (more than 100 by 1976). Collectors usually concentrate on issues of definite areas (e.g., the Scandinavian countries) or on such specialties as airmail or commemorative stamps, stamps depicting subjects such as bridges, trades, or animals, or covers with special markings.