The British Library is the national library of the United Kingdom and the second largest library in the world.
To the library community and the public at large, the best-known component of the new national library consisted of the library departments of the British Museum. The Museum's Department of Printed Books was founded in 1753, the year of the foundation of the Museum itself. Over the intervening two hundred years, the library of the British Museum had grown into one of the largest in the world, sustained by its privilege of legal deposit whereby it was entitled to a copy of most items printed in the United Kingdom - not only books and periodicals, but newspapers, maps, and printed music. In addition, the Museum's comprehensive holdings of non-legal deposit items had reportedly earned it the accolade from Lenin of possessing (in the 1900s) a more comprehensive collection of Russian books than libraries in Moscow and St Petersburg.