Indexing and Identification of Library materials

Indexing is a superior technique for retrieving relevant information contained in documents stored in the Library. The access points in indexing are analyzed in order to bring out the subject terms that have been sufficiently treated. For each of the subject terms that have been chosen as an access point using indexing techniques, the bibliographic details of the document will be provided and Users who have interest in the different subject areas that have been covered will be able to locate the same documents.

Indexing is the process by which the content of an information resource is analyzed, and the “aboutness” of that item is determined and expressed in a concise manner. Indexing is also concerned with describing the information resource in such a way that users are aware of the basic attributes of a document, such as author, title, length, and the location of the content. Indexing typically concerns textual items only; although image indexing is a growing area of practice.

Types of classification of library materials

A Library classification is a system of knowledge organization by which library resources are arranged and ordered systematically. Library classifications use a notational system that represents the order of topics in the classification and allows items to be stored in that order. In Nigeria, there are two forms of library classification used for the identification of materials within the library system:

1. Library of Congress Classification

The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress. It is used by most research and academic libraries in the U.S. and several other countries. The Library arranges its collections of books and bound periodicals according to the Library of Congress Classification Scheme. Each book has a class mark consisting of letters and numbers which indicate its subject and determine where it is filed on the shelf.

The code usually begins with two letters:

• The first letter represents the broad subject. For example, all D books (History) are on the Second Floor.
• The second letter specifies a narrower subject area within the broad category: within History (D), DA stands for British History.
• The next part of the class mark is a number, which gives a more precise definition of subject matter. Within a subject section, books are filed numerically, so DA 84 comes before DA 86 which comes before DA 226.
• The final part of the class mark refers to the author's name. It normally consists of a letter and a number. This part is filed in alphabetical order by letter, then by number in a decimal sequence, i.e. DA 84.C3 precedes DA 84.C35 which precedes DA 84.C4.

2. Dewey Decimal Classification, also called Dewey Decimal System

This is a system for organizing the contents of a library based on the division of all knowledge into 10 groups, with each group assigned 100 numbers. The 10 main groups are: 000–099, general works; 100–199, philosophy and psychology; 200–299, religion; 300–399, social sciences; 400–499, language; 500–599, natural sciences and mathematics; 600–699, technology; 700–799, the arts; 800–899, literature and rhetoric; and 900–999, history, biography, and geography.

These 10 main groups are in turn subdivided again and again to provide more specific subject groups. Within each main group the principal sub series are divided by 10; e.g., the history of Europe is placed in the 940s. Further subdivisions eventually extend into decimal numbers; e.g., the history of England is placed under 942, the history of the Stuart period at 942.06, and the history of the English Commonwealth at 942.063.