Classified catalogue is primarily a subject catalogue arranged on the basis of notation. This is its original form. Margret Man had define classified catalogue thus. But arrangement by notation or class number alone can satisfy only subject approach and author approaches will remain unsatisfied resulting in limited use of classified catalogue. We know that a common reader approaches the library and the catalogue by author or title. Keeping this fact in view Ranganathan define classified catalogue as a catalogue in which some entries are number entries and some are word entries. Thus classified catalogue has two parts, classified part and alphabetical part. Classified part is the main part and alphabetical part is index or secondary part. Classified part contains number entries i.e. subject entries and cross reference entries. These are arranged according to the call numbers assigned according to the scheme of classification used. The alphabetical or index part contains index or added entries which are arranged alphabetically.
Qualities of classified catalogue:
(i) In classified part of classified catalogue number entries are arranged in classified order bringing together entries for related subjects in a logical and filiatory order as under:
(ii) Main entry in it is number entry. Word entries have their own limitations because meaning of a words at different places etc. Numbers are free from these limitations. (All of the Subject entries are stand together).
(iii) Classified catalogue gives a more true picture of the collection of a library because in it entries are arranged in the order in which books are kept in shelves.
(iv) It reveals with much accuracy the strength and weakness of the collection on a subject and thus warns the librarian of unbalanced growth of the collection.
(v) Classified catalogue of bigger libraries can serve as subject bibliographies and book selection tools for smaller entries.
Weaknesses of Classified Catalogue:
- General or common reader is not expected to be aware of the classification system used for arranging the entries. He therefore, first refers to the index part and then to the main or classified catalogue. Process of search therefore, become longer and time consuming.
- Defects in scheme of classification, if any, makes the catalogue defective. for example, if Dewey Decimal classification is used then entries relating to language and literature – the two related subjects will be placed far from one another.
- Due to advancement in a particular subject field the class number of the field may need reconstruction. In such cases the catalogue will also have to be reconstituted.