Because nonfiction books are so useful in your research, it's important for you to understand how they are organized in a library. The Dewey Decimal System was created early in the 20th century to help public and school libraries organize their books, and to help library visitors find the books they need. Each number in the system (000, 100, 200, etc.) corresponds to a broad topic, and more narrow topics are given a higher number, with the most specific books labeled with a number containing a decimal, such as 516.3. For example, here is a list of topics related to math. Each time the number gets a little higher, the topic gets more specific.

The shelves of most reference libraries are labeled with the numbers of the Dewey Decimal System. To find a book about Finsler geometry, you would look for a book with the number 516.375 on its cover. (The Dewey Decimal number usually appears on a book's spine, where you can see it as you stand in the aisle between shelves).

Click through the slideshow to see a general breakdown of topics in the Dewey Decimal System.

000 Generalities Data Processing Computer Science Library Information and Sciences General Encyclopedias New Media Journalism 100 Philosophy and Psychology Philosophy Paranormal Phenomena (Occult, Witchcraft, Astrology, ESP, Ghosts, Dreams, etc.) Psychology Logic Ethics 200 Religion Theory of Religion The Bible Christianity Practice and Observance Religious Orders History and Denominations World Religions 300 Social Sciences Sociology Anthropology Political Science Economics Law Military Science Education Commerce, Communication, and Transportation Customs and Folklore 400 Language Linguistics World Languages Dictionaries 500 Natural Sciences and Math Math Astronomy Physics Chemistry Earth Sciences Life Sciences and Biology Plants Wild Animals 600 Technology (Applied Sciences) Medical Sciences Engineering Agriculture, Farm Animals, and Pets Home Economics and Family Living Business Management Manufacturing Buildings and Construction 700 The Arts Civic and Landscape Art Architecture Sculpture Drawing and Decorative Arts Painting Graphic Arts Photography Music Performing Arts Sports, Games, and Outdoor Activities 800 Literature Literature of all Languages Poetry Drama Fiction Essays Speeches Letters Humor and Satire 900 Geography, History, and Biography Geography Travel Biography Ancient World Europe Asia Africa North America South America Extraterrestrial Worlds

Of course, no Dewey Decimal chart can contain all of the topics included in each set of hundreds. You have to draw conclusions based on which general topic is most like your specific one. Give it a try, using the activity below. Try matching each number where books about that topic would be found to the topic. Look back at the chart above to remind yourself of the numbers and their topics.