"Books are for use" is the first, most basic law of library science. While this seems simple and self-evident, librarians at the time felt very conflicted between the desire to promote reading and the urge to protect and conserve their books. Ranganathan maintained that books should be used, read and circulated.
An extension of "books are for use," the second law asserts the right of a library patron to have access to any of the library's books.
The converse of the second law, this third statement asserts that at least one community citizen will have an interest in every book in the library, and that every book should be available for that person.
This guideline is meant to improve the efficiency of the library. Readers who can quickly locate the book they want will be more satisfied customers.
Ranganathan realized that libraries need to continually grow in order to survive. They should be constantly accumulating more books in their collection, and they should continually adapt to changes in culture, interest and technology.