The smell of old books that range from "woody" through to vanilla or "rotten socks" have been coded by scientists to help preserve the nation's treasures.
Visitors to St Paul's Cathedral described the smell coming from old texts. Researchers used their answers along with chemical analysis to help conservationists identify books that are in danger of perishing.
Scientists at University College London's Institute for Sustainable Heritage created a 'Historic Book Odour Wheel' to document and archive the aroma associated with antique manuscripts.
'Woody' was the most frequently described followed by
The intensity of the smells was assessed as between 'strong odour' and 'very strong odour'.
Over seven in ten described the smell as pleasant while a sixth described it either as 'mildly pleasant' or 'neutral'.
Cecilia said certain smells could be considered part of our cultural heritage so there was a need to identify, protect and conserve them.