The first modern libraries were established in the mid 19th century in Britain, and public libraries were not widespread in the United States until the late 19th and early 20th centuries. Before that, most libraries were private, and only a select few had access to them. It is difficult to say who invented the library system as it was a gradual development over many centuries, but some key figures in the development of libraries include:
* Panizzi, Antonio (1797-1879): Panizzi was an Italian-British librarian who served as the principal librarian of the British Museum from 1856 to 1866. He is credited with modernizing the British Museum library and introducing many of the practices that are still used in libraries today, such as the use of catalog cards and the open-stack system.
* Melvil Dewey (1851-1931): Dewey was an American librarian who is best known for developing the Dewey Decimal Classification system, a system for organizing library materials by subject. The Dewey Decimal Classification system is used by libraries all over the world.
* Sarah Josepha Hale (1788-1879): Hale was an American writer and editor who is credited with being the founder of the first public library in the United States. The Peterborough Town Library in Peterborough, New Hampshire, was founded in 1833 thanks in large part to Hale's efforts.