Your Free Guide to Finding Books in the Library

Understanding How Public Libraries Organize Books

Public libraries use two main systems to organize their book collections: the Dewey Decimal System and the Library of Congress Classification System. The Dewey Decimal System is the most common method used in public libraries across the United States. Created in 1876 by Melvil Dewey, this system divides all knowledge into 10 main classes, each represented by numbers from 000 to 999. Each class breaks down further into more specific subcategories, allowing librarians to assign a unique number to virtually every book published.

The Dewey Decimal System works like this: books numbered 000-099 cover general knowledge and computer science, 100-199 cover philosophy and psychology, 200-299 cover religion, 300-399 cover social sciences, 400-499 cover language, 500-599 cover natural sciences and mathematics, 600-699 cover technology and applied sciences, 700-799 cover arts and recreation, 800-899 cover literature, and 900-999 cover history and geography. Within each hundred-number range, the decimals allow even more precision. For example, books about dogs might be numbered 636.7, while books about cats might be 636.8.

The Library of Congress Classification System, used primarily in academic and large research libraries, uses letters instead of numbers. This system includes 21 main classes represented by single letters (A through Z, excluding some letters), with additional letters and numbers providing more specific categorization. While you may encounter this system in college or university libraries, most public libraries use Dewey Decimal.

Understanding these systems helps you navigate the library more effectively. Most libraries display these classification numbers clearly on book spines, using colored labels or printed text. The reference desk staff can explain how these systems work in your specific library, since some libraries use slight variations of the standard systems.

Practical Takeaway: Before your next library visit, ask a librarian to show you where a few specific topics are shelved. This hands-on experience will help you understand your library's organization system and make future searches faster.

Using the Library Catalog to Search for Books

Nearly every library maintains a catalog—either physical cards (in older libraries) or, more commonly, a digital database accessible from computers throughout the library or from home. The library catalog is essentially an index of everything the library owns. Learning to search this catalog effectively can save you significant time and frustration.

Most library catalogs allow you to search by several methods: by title (if you know the exact book name), by author (if you know who wrote the book), by subject (if you're looking for information about a topic), or by keyword (which searches multiple fields at once). When searching by title, you don't need to include the words "the," "a," or "an" at the beginning. For example, to find "The Great Gatsby," simply search for "Great Gatsby." When searching by author, enter the last name first (Smith, John rather than John Smith), though many modern catalogs accept either format.

Subject searching is particularly useful when you want to explore a topic but don't have a specific book in mind. Libraries organize subjects using standardized headings called Library of Congress Subject Headings. For instance, instead of searching "books about dogs," you might search the subject heading "dogs—behavior" or "dogs—training." The catalog will show you all books tagged with that subject. If your first search doesn't return results, try alternative subject terms—a book about "automobiles" might also be listed under "motor vehicles" or "transportation."

When you find a book in the catalog, note several key pieces of information: the title, author, call number (the Dewey Decimal or Library of Congress number), and availability status. The catalog will indicate whether the book is currently on the shelf, checked out, or in another location if your library system includes multiple branches. Many catalogs also show how many people are waiting to check out a particular book, helping you decide whether to place a hold or look for an alternative.

Modern library catalogs often include additional features: user reviews and ratings from other patrons, book summaries, links to related books, and sometimes even the ability to preview pages or read sample chapters. Some catalogs allow you to create an account and maintain a wishlist of books you want to read.

Practical Takeaway: Visit your library's website and spend 15 minutes exploring its catalog. Search for three books: one by title, one by author, and one by subject. This will familiarize you with your library's specific search interface and help you understand what information is available about each book.

Finding Books on the Shelves

Once you've located a book in the catalog and noted its call number, the next step is finding it on the library shelves. Libraries arrange books in numerical or alphabetical order based on their classification system. In a Dewey Decimal library, books are shelved from left to right, starting with 000 series and progressing through to the 900 series. Within each section, books are arranged in numerical order by their full call number, including decimals.

Call numbers often appear in multiple lines on a book's spine. For example, a call number might look like this when read vertically down the spine: 641.5 / Smith. The first number indicates the general subject area (in this case, cooking or food), and what follows provides more specific information. When looking for books on a shelf, first locate the general section by the first digits, then scan for the more specific numbers. If you're looking for call number 641.567, you first find the 641 section, then look for books numbered 641.5, then 641.56, and finally 641.567.

Libraries organize shelves to maximize space and make browsing intuitive. The main circulation stacks (where most books are shelved) are usually marked with clear signage indicating which call number ranges are located in each section. If you're unable to find a particular section, look for these directional signs or ask a staff member for help locating a specific call number range.

When you reach the correct shelf section, take a moment to look at the books around the call number you're seeking. Libraries shelve related books near each other, so you may discover other relevant books while searching. A book on "cookie decorating" might be shelved next to books on "cake design" and "bread baking," allowing you to explore related topics without additional searching.

If a book you found in the catalog isn't on the shelf, several reasons could explain this: someone else is currently checking it out, it may be on a cart awaiting reshelving, it might be at another branch, or it could be temporarily unavailable for repair or processing. Your library's catalog should indicate the book's status. Many libraries allow you to place a hold on checked-out books, and staff will notify you when the book becomes available.

Practical Takeaway: Select a call number for a book in a subject that interests you and practice finding it on the shelves. Pay attention to the books shelved nearby—you may find additional resources that match your interests.

Exploring Different Sections and Collections

Public libraries typically organize materials into several distinct sections, each serving different purposes and readers. Understanding what exists beyond the main fiction and nonfiction stacks will significantly expand your research and reading options. Most libraries maintain a reference section, which includes encyclopedias, dictionaries, atlases, and other materials designed for quick consultation. Reference books traditionally don't check out; they must remain in the library so they're available for all patrons. However, many libraries now allow photocopying of reference materials or have created digital versions that you can access from home.

The periodicals section houses magazines, journals, and newspapers. Libraries may keep recent issues in an open display and store older issues in bound volumes or microfilm. Browsing the periodicals section can be an excellent way to find current information on topics, read opinion pieces, or discover specialized magazines related to hobbies or professions. Many libraries now include digital access to periodicals through online databases available to library patrons.

Most public libraries maintain separate young reader collections: children's sections for picture books and chapter books for younger children, and young adult sections for teenagers. These sections are organized similarly to adult collections but often use simpler language in book summaries and categorization. If you're searching for books for a child or young adult, librarians in these specialized sections can provide thoughtful recommendations based on reading level and interests.

Many libraries now feature special collections or archives containing local history materials, rare