The British Library is the national library of the United Kingdom and the largest library in the world by number of items catalogued. It is estimated to contain 170–200 million items from many countries.
As a legal deposit library, the British Library receives copies of all books produced in the United Kingdom and Ireland, including a significant proportion of overseas titles distributed in the UK. The Library is a non-departmental public body sponsored by the Department for Culture, Media and Sport.
The British Library is a major research library, with items 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. In addition to receiving a copy of every publication produced in the UK and Ireland (approximately 8,000 per day), the Library has a programme for content acquisitions.
The Library adds some three million items every year occupying 9.6 kilometres (6.0 mi) of new shelf space. There is space in the library for over 1,200 readers.
Prior to 1973, the Library was part of the British Museum. The British Library Act 1972 detached the library department from the museum, but it continued to host the now separated British Library in the same Reading Room and building as the museum until 1997.
The Library is now located in a purpose-built building on the north side of Euston Road in St Pancras, London (between Euston railway station and St Pancras railway station), and has a document storage centre and reading room near Boston Spa, near Wetherby in West Yorkshire.
The St Pancras building was officially opened by Queen Elizabeth II on 25 June 1998, and is classified as a Grade I listed building "of exceptional interest" for its architecture and history.
According to en.wikipedia