More recently, libraries are understood as extending beyond the physical walls of a building, including material accessible by electronic means, and providing assistance by librarians in navigating and analyzing the tremendous amounts of knowledge with a variety of digital tools. The term 'library' has itself acquired a secondary meaning: "a collection of useful material for common use", and in this sense is used in fields such as computer science, mathematics and statistics, electronics and biology. Estate Planning Library

Many potential library patrons nevertheless do not know how to use a library effectively. This can be due to lack of early exposure, shyness, or anxiety and fear of displaying ignorance. These problems drove the emergence of the library instruction movement, which advocates library user education. Library instruction has been practiced in the U.S. since the 19th century. One of the early leaders was John Cotton Dana. Library instruction is closely related to the study of information literacy.

Libraries inform the public of what materials are available in their collections and how to access that information. Before the computer age, this was accomplished by the card catalog - a cabinet containing many drawers filled with index cards that identified books and other materials. In a large library, the card catalog often filled a large room.