Other libraries keep famous or rare books. There are a few "Copyright libraries" which have a copy of every book which has been written in that country. Some libraries also have other things that people might like, such as magazines, music on CDs, or computers where people can use the Internet. In school they offer software to learn the alphabet and other details.With the spread of literacy, libraries have become essential tools for learning. Libraries are very important for the progress and development of a society.Libraries are collections of books and other informational materials. People come to libraries for reading, study or reference. Libraries contain a variety of materials. They contain printed materials, films, sound and video recordings, maps, photographs, computer software, online databases, and other media.