The British Library is the national library of the United Kingdom. The library is a major research library, holding over 150 million items from many countries, in many languages and in many formats, both print and digital: books, manuscripts, journals, newspapers, magazines, sound and music recordings, videos, play-scripts, patents, databases, maps, stamps, prints, drawings. The Library's collections include around 14 million books, along with substantial holdings of manuscripts and historical items dating back as far as 2000 BC. The British Library is the largest library in the world by number of items catalogued. However, such metrics are of limited utility due to the variety of cataloguing methods employed by institutions.