The Duchess of Kent is set to officially reopen Watlington library in Oxfordshire after a £700,000 revamp.
The building is now twice the size it was with more books, public computers and a dedicated children's area.
The Friends of Watlington Library (Fowl) raised £50,000 towards the costs of the improvements which have led to a 200% increase in the library's usage.
Kelvin Eveleigh, the library's customer services manager, said: "The situation is very rosy for us at the moment."
Fowl have been campaigning for library services in the town for the past 15 years.
They initially fought for two years to prevent the library's closure then raised funds to expand and modernise its facilities.
Work started on the project last year and it opened to the public on 27 September.
Because the building is listed, the size of the library was doubled by constructing an extension at the back.