The British Library, home to documents ranging from Magna Carta manuscripts to handwritten Beatles lyrics, has become one of England's youngest buildings to receive protected status.
The library, the largest public building to be built in the UK in the 20th century, has been given the highest Grade I listed status for its outstanding architectural and historic interest, experts said.
The Government has also listed seven 20th century libraries across England at Grade II.
Originally designed by architect Sir Colin St John Wilson and his partner MJ Long, the construction of the British Library on the Euston Road, London, began in 1982 and was completed in summer 1997, with doors opened to readers later that year.
Moving the books into the £506 million building took four years and was finally completed in 1998.
The design includes five public floors sweeping upwards from the entrance, with 11 reading rooms surrounding the centrepiece of the King's Library tower containing George III's library.
The library is home to the "treasures gallery" which holds books and documents including two original Magna Carta manuscripts, Lindisfarne Gospels, Shakespeare's First Folio, Gutenberg's 1455 Bible, and Handel's Messiah written in the composer's hand.
With its new protected status, it joins other listed buildings in the vicinity including Grade I St Pancras Hotel and station and Grade I King's Cross station.
Heritage Minister Tracey Crouch said: "The British Library divided opinion from the moment its design was revealed, but I am glad that expert advice now allows me to list it, ensuring that its iconic design is protected for future generations to enjoy."
Director of listing at government heritage body Historic England, Roger Bowdler, described it as "one of England's finest modern public buildings".
He said: "Listing it at Grade I acknowledges its outstanding architectural and historic interest. Colin St John Wilson's stately yet accessible design incorporates fine materials and a generous display of public art.
"The library's dramatic and carefully considered interiors achieve its ultimate goal: of creating a space to inspire thought and learning."
The awarding of Grade I status to the British Library means it joins Lloyd's of London, in the City of London, as the youngest buildings in England to be listed.
British Library chief executive Roly Keating welcomed the highest level of listing for Colin St John Wilson's "courageous and visionary design" for the building.
"Even in the relatively short period since its opening it has worked its way into the affections of millions of visitors and researchers, who have discovered its beautiful spaces, subtle use of natural light and exquisite detailing.
"It is also a privilege to be listed alongside a group of distinguished public library buildings from across the country.
"As well as celebrating architectural excellence, this listing is a reminder, in the midst of the digital age, of the vital importance of libraries as physical spaces of the highest quality at the heart of their communities," he said.
The seven libraries across England listed at Grade II, their dates of construction and architects, are:
:: Suffolk Record Office, Suffolk, 1963-5, Donald McMorran;
:: Bebington Central Library, The Wirral, 1967-71, Paterson, Macaulay and Owens;
:: Milton Keynes Central Library, Milton Keynes, 1979-81, Buckinghamshire County Council architects;
:: Chandler's Ford Library, Eastleigh, Hampshire, 1981-2, Hampshire County Council architect Colin Stansfield Smith
:: West Sussex Library, West Sussex,1965-6, county architect F R Steele;
:: Bourne Hall Library & Social Centre, Epsom, Surrey, 1967-70, A.G. Sheppard Fidler and Associates;
:: Lillington Library, Leamington Spa, Warwickshire, 1959-60, Henry Fedeski.