Legal deposit is a legal requirement that a person or group submit copies of their
publications to a repository, usually a
library. The requirement is mostly limited to books and
periodicals. The number of copies varies and can range from one to 19 (in Poland). Typically, the
national library is one of the repositories of these copies. In some countries there is also a legal deposit requirement placed on the government, and it is required to send copies of documents to publicly accessible libraries.