They want to answer your questions. Always ask a librarian for help if you are confused or cannot find something. Let's say you have a paper due in your history class. Your teacher has asked you to write about a famous American leader. To find books, you will need to use the card catalog.
Some libraries have both kinds.
To use the print card catalog, you should begin with the subject listings. This is the part of the card catalog that lists books by subject, or what the book is about. Jr. This is because people are listed in the card catalog by their last names. Titles like Dr. are not included on catalog cards. Each card with the heading King, Martin Luther, Jr. will describe a book on your subject.