Subject: library classification systems Libraries Classification Scheme Classification Provides a system for Organizing A universe of items which the Libraries usually arrange it's collections according to the systematic structure of Classification, so there are many classification scheme in the world but the famous three classifications are Dewey Decimal Classification, The Universal Classification and the Library of congress Classification, concerning the environmental library it's better to use DDC because it's the most widely used library classification system in the world, it's used more than 135 countries and has been translated into over 30 languages, the notation in DDC is the system of symbols used to represent the classes in a classification system, it gives the unique meaning of the class and it's relation to other classes, it permits the searcher to find a specific item withen the class to which it belongs and near related classes, the DDC is devided into ten main classes which togother cover the entire world of knowledge, these classes are further divided into ten divisions and each division into ten section: The ten main classes are: 000 Generalities 100 Philosophy 200 Religion 300 Social Sciences 400 Languages 500 Natural Sciences (Pure Science) 600 Technology (Applied Science) 700 the Arts 800 Literature 900 History & Geography For example: Clssification of Environmental Engineering in DDC 600 Technology 620 Engineering 628 Environmental Engineering 628.1 Water Supply 628.2 Sewers & Sewage 628.3 Sewage Treatment 628.4 Waste Technology 628.42 Hazardous Waste 628.43 Liquid Waste 628.44 Solid Waste Best regards Hani Kordiya Environmental planning Directorate - Gaza - -