Reference Materials: Some books, such as encyclopedias, dictionaries, and study aids, are meant to be used as quick references within the library. These books are often valuable resources for on-the-spot information and are kept within the library to ensure they are readily available for all users.

High Demand or Limited Copies: In cases where a book (e.g. textbook) is in high demand or there are limited copies available, a library may designate it as in-library use only to ensure fair access for all users. This policy helps prevent a popular book from being checked out for an extended period, allowing more people to benefit from its content.