Melvil Dewey was a librarian who was born in Adams Centre, New York, USA on December 10, 1851 and died December 26, 1931. He was the Librarian who invented a decimal classification system for library books called "Dewey Decimal System". This was first published in 1876.
The great thing about the Dewey Decimal System is that you can go into any library in the world and still find items based on what area they come under.
Here is what each part of the Dewey system stands for:
000-009 General Works (Encyclopedias etc)
100-199 Psychology & Philosophy
200-299 Religion & Mythology
300-399 Social Sciences
400-499 Languages
500-599 Natural Science & Mathematics
600-699 Applied Science & Technology
700-799 Fine Arts & Recreation
800-899 Literature & Poetry
900-999 Geography & Hisotry
Check out this dewey site to learn more and test your knowledge with some fun games.
http://library.thinkquest.org/5002/?tqskip=1