Hello Latasha!
The Dewey Decimal Classification System is a library classification system first published in the U.S. by Melville Dewey in 1876.
It consists 20 main classes:
000-099 General Works
100-299 Philosophy, Psychology and Logic
200-399 Religion
300-499 Social Sciences
400-599 Natural Sciences
500-699 Technology and Applied Sciences
600-799 Fine Arts and Recreation
700-899 Literature
800-999 History and Biographies
