b'PrefaceForm of HeadingsIt was the policy of Minnie Sears to use the Library of Congress form of subject headings with somemodification, chiefly the simplification of phrasing. The Sears List still reflects the usage of theLibrary of Congress unless there is some compelling reason to vary, but those instances of variationhave become numerous over the years. A major difference between the two lists is that in Sears thedirect form of entry has replaced the inverted form, on the theory that most library users search formultiple-word terms in the order in which they occur naturally in the language. In most casescross-references have been made from the inverted form and from the Library of Congress formwhere it otherwise varies.Scope NotesAs in previous editions, all the new and revised headings in this edition have been provided withscope notes where such notes are required. Scope notes are intended to clarify the specialized use ofa term or to distinguish between terms that might be confused. If there is any question of what aterm means, the cataloger should simply consult a dictionary. There are times, however, whensubject headings require a stricter limitation of a term than the common usage given in a dictionarywould allow, as in the case of Marketing, a term in business and economics, not to be confusedwith Grocery shopping. Here a scope note is required. Some scope notes distinguish betweentopics and forms, such as Encyclopedias and dictionaries for critical and historical materials andthe subdivisions Encyclopedias and Dictionaries under topics for items that are themselvesencyclopedias or dictionaries. There are also scope notes in Sears that identify any headings in thearea of literature that may be assigned to individual works of drama, fiction, poetry, etc.ClassificationThe classification numbers in this edition of Sears are taken from the Abridged WebDewey, thecontinuously updated online version of the Abridged Dewey Decimal Classification. The numbersare intended only to direct the cataloger to a place in the DDC schedules where material on thatsubject is often found. They are not intended as a substitute for consulting the schedules, notes, andmanual of the DDC itself when classifying a particular item. The relationship between subjectheadings and classification is further discussed in the Principles of the Sears List.Usually only one number is assigned to a subject heading. In some cases, however, when a subjectcan be treated in more than one discipline, the subject is then given more than one number in theList. The heading Chemical industry, for example, is given two numbers, 338.4 and 660, whichrepresent possible classification numbers for materials dealing with the chemical industry from theviewpoints of economics and technology respectively. Classification numbers are not assigned to afew very general subject headings, such as Charters, Exhibitions, Hallmarks, and Identification,which cannot be classified unless a specific application is identified. The alphabetic notation of Bfor individual biographies is occasionally provided in addition to Dewey classification numbers forsuch materials. Numbers in the 810s and 840s prefixed by a C are given as optional numbers fortopics in Canadian literature.The Dewey numbers given in Sears are extended as far as is authorized by the Abridged DeweyDecimal Classification, which is seldom more than four places beyond the decimal point. When anitem being classified has a particular form or geographic specificity, the number may be extended byA-9'