Whether searching for materials in the library or exploring the Web, you just need to know how to find your way around. The Library Books in the library are arranged by subject. In 1876, a librarian named Melvil Dewey created a system for organizing books which we call the Dewey Decimal Classification System. According to his classification scheme, there are ten categories of numbers. For example, you will find a book on geography in the 900's and one on natural sciences in the 500's.
All libraries have a reference collection of dictionaries, almanacs, encyclopedias, etc.
These materials are also classified and shelved according to Dewey. For example, a dictionary of astronomy will be in the 520's in the reference section. To find a list of books on a certain topic, you will need to use the library's catalog. You can find everything from adopting a humpback whale to weather maps. The resources on the web are so vast and intertwined that search engines and web directories were created to help retrieve what you are looking for.