b'The Grammar of Subject Headings / Subdivisionssubdivisions specify the form an item takes. Like form headings they tell what an item is rather thanwhat it is about. Some of the most common form subdivisions are Bibliography; Catalogs;Dictionaries; Directories; Gazetteers; Handbooks, manuals, etc.; Indexes; Maps; Pictorial works;Portraits; Registers; and Statistics.Topical headings with form subdivisions, such as Childrens literatureBibliography orGeologyMaps, render such works retrievable by form and separate them from expositorytreatises. Apart from a few examples, these combinations of subject heading with form subdivisionare not given in the Sears List but are to be added by the cataloger as needed. Form subdivisions areparticularly valuable under headings for the large fields of knowledge that are represented by manyentries in a librarys catalog. In applying form subdivisions the cataloger should be guided by thecharacter of an item itself, not by the title.Many works with titles beginning with Outline of, Handbook of, or Manual of, are in factexpository works. For example, H. G. Wellss Outline of History and H. J. Roses Handbook ofLatin Literature are lengthy, comprehensive treatises, and to use the form subdivisions that the titlessuggest would be inaccurate. Other so-titled Outlines or Manuals or Handbooks may prove to bebibliographies, dictionaries, or statistics of the subject.The Order of SubdivisionsAt the Subject Subdivision Conference that took place at Airlie House, Virginia, in May 1991,organized by the Library of Congress, it was recommended that subdivisions follow the standardorder of [Topical][Geographic][Chronological][Form]. Since that time the librarycommunity has endeavored to implement that recommendation. Only in a few subject areas,especially in the field of art, have exceptions been made. A cataloger using the Sears List can safelyassume that subject strings made in the recommended order will provide the greatest uniformity. Byfollowing this standard the cataloger will know, for example, to prefer Elderly - HousingUnitedStates to ElderlyUnited StatesHousing, and SportsUnited StatesStatistics toSportsStatisticsUnited States. (Housing is a topical subdivision, and Statistics is a formsubdivision.)The order of subdivisions also indicates against subdividing any subject heading in the Listgeographically that already incorporates a chronological or form subdivision. The headingPhysiciansDirectories, for example, would not be subdivided by Ohio, because the correctorder of subdivisions would be PhysiciansOhioDirectories.Geographic Headings Subdivided by TopicA longstanding exception to the practice of subdividing topics geographically, and one that remainsapart from the Airlie House recommendation, is that of subdividing geographic headings by topics,when those topics pertain to the history, geography, or politics of a place. For works discussing thehistory of California, a census of Peru, the government of Italy, the boundaries of Bolivia, thepopulation of Paris, or the climate of Alaska, the appropriate subject strings would be California A-31'