Basics of Dewey (don't ask a clerk, we don't know)

One balmy morning, shortly after opening the branch, a guy walks in and asks for books on the...how can I forget this...the tranquility of fish tanks. So like, um...ask the librarians at the reference desk i says, pointing the way. Soon after, I see the guy leaving, dejected and bookless. So I figured i'd at the very least learn basics of the the DDC. Now if you really want to know where particular books are in the library, ask a messenger clerk, they are the ones who put the books back on the shelves. Just don't ask a clerk. So here goes...

HOW DEWEY DECIMAL CLASSIFICATION (DDC) WORKS

Dewey divided knowledge into nine classes plus one "Miscellaneous," each assigned a numerical range:

000 General Works (Miscellaneous)
100 Philosophy
200 Religion
300 Social Sciences
400 Languages
500 Pure Sciences
600 Technology (Practical Arts) including medicine, engineering, business accounting, agriculture, salesmanship, etc.
700 Fine Arts (including architecture, painting, photography, music, amusements, etc.)
800 Literature
900 History, Geography, Biography

Melvil Dewey, pencil-neck geek, "Father of Modern Librarianship", god of small things, devised, what would become the most widely used method of organizing/classifying books in the U.S. and the world (let us not mention the Library of Congress classification system ;) . The straightdope.com staff breaks it down even further:

"Each item that comes under one of these disciplines is assigned a number in that range, called a class number. The logic is hierarchical: that is, within a main class, there are various subdivisions (called subclasses), and these are subdivided further, getting more specific. For example, within 700 (the arts) we have 790 ("Recreational and Performing Arts"), and within that is 795 for games of chance. After the three leading numbers, decimals can be used for as much further subdivision as needed, so 795.4 is card games, 795.41 is card games "based chiefly on skill," 795.415 is contract bridge, and 795.4152 is the bidding process (auction) in contract bridge.

A hallmark of DDC is the use of consistent subclassifications and mnemonics regardless of category. For example, 73 usually refers to the U.S., on both sides of the decimal point; thus, U.S. cooking is 631.5973 and U.S. history is 973. In contrast, LCC (Library of Congress Classification) subclassifications have no consistency from one class to the next."

(from straightdope.com, for full explaination/history/comparisons with LLC/Dewey himself go to: http://www.straightdope.com/mailbag/mdeweydecimal.html )

Got it? If not, ask a messenger clerk.