Like Library of Congress call numbers, Dewey Decimal call numbers group books together by broad topic or classification (number before the decimal), and then use further letters and numbers to group books into more specific topics and subtopics (letters and numbers after the decimal).
While the call numbers appear horizontally in the online catalog, they will appear vertically on the spine or edge of the book.
For example, to read the Dewey Decimal call number in the catalog: 630.51 P884
630.51: The number in front of the decimal is read as a whole number (six hundred and thirty), then treat the rest as a decimal. 630.51 would come between 630.5 and 630.52.
P884: For the final number, go to the letter first and then read the rest as the whole number. P884 would come between P883 and P885.
Example taken from the U. of Chicago libraries.
The call number appears horizontally on the spine:
Call numbers group materials on similar subjects together to facilitate browsing. So, if you find one book that closely matches your topic, you will likely find others next to it on the shelf that fit with your research. The beginning letters of a Dewey Decimal call number indicate what broad classification your book is in.
100 Philosophy & psychology
300 Social sciences
500 Natural sciences & mathematics
600 Technology (Applied sciences)
700 The arts
800 Literature & rhetoric
900 Geography & history
Deweys in the Owen Science Library are on the 3rd floor. Look for the signs as you get out of the elevator.
Dewey call numbers in the Holland & Terrell libraries are located on the Basement floor in Compact shelving. (see map below)
Holland and Terrell Basement Floor