The Dewey Decimal system is a method to arrange books by subjects. It is used by most public libraries and many college libraries to catalogue and shelve books. The Dewey Decimal number indicates the main subject of the book and dictates where it should be shelved. These numbers are not set in stone, and the person cataloguing the item must use his/her discretion when assigning a number. Most books have slightly different Dewey Decimal Numbers depending on the library.
Visit your local library's catalogue. Most libraries have an online catalogue that can be accessed from the Internet.
Search for the book you are interested in. The catalogue will display books with the same or similar titles.
Find the exact book that you want and click for more details. Look under the call number or classification system for the Dewey Decimal Number.