Hệ thống thập phân Dewey được thiết kế để phù hợp với tất cả các thư viện, Thư viện Quốc hội Mỹ hệ thống được tạo ra để phù hợp với một thư viện cụ thể, Thư viện Quốc hội. Tuy nhiên, hệ thống phân loại này đã chứng tỏ sự hữu ích mà hiện nay được sử dụng bởi gần như tất cả các thư viện lớn | library that has several books on computer technology files them all under the same call number but shelves them alphabetically. Library of Congress Classification System The Dewey Decimal System was designed to suit all libraries the Library of Congress system was created to suit one specific library the Library of Congress. However this classification system proved so useful that it is now used by nearly all large libraries especially those in colleges and universities. Each Library of Congress classification number contains three lines A letter at the top. A number in the middle. A letter number combination at the bottom. The Library of Congress classification system has 20 classes A General works B Philosophy and religion C History D History and topography except America E-F American history G Geography anthropology folklore manners cus- toms recreation H Social sciences J Political sciences K United States law L Education M Music N Fine arts P Language and literature Q Science R Medicine 46 S Agriculture T Technology U Military science V Naval science Z Bibliography and library science As with the Dewey system each of the categories in the Library of Congress system can be divided into subclasses. Because the Library of Congress system groups related topics you can often find unexpected but related avenues to pursue as you research. As a result it s not a bad idea to take a few minutes to browse the shelves as you gather books you need. Warning Unfortunately library call numbers don t work like the Celsius and Fahrenheit temperature systems. There is no way to convert the call numbers in one system to those in the other system. So you cannot take the call numbers from a library that uses the Dewey classification system to a library that uses the Library of Congress classification system. You have to look the book up again if you work with two systems so it s usually a good idea to pick one library system for books - either the public library system or the .
