Blackpool Central Library has closed for 12 months to undergo a major refurbishment.
The project will create a new extension to house new community and technology areas and a cafe.
Library users will be able to use Revoe, Layton and Palatine Libraries, which will have their opening hours extended from 6 September.
Blackpool Council said the library will reopen in its centenary year 2011.
Councillor Tony Williams, cabinet member for culture and communities at Blackpool Council, said: "Central Library is a truly iconic building that is significant not just in Blackpool's history but nationally as one of the small collection of original Carnegie buildings that set a benchmark for all libraries and brought learning to the masses.
"This is still apparent today as Central Library remains one of the busiest public buildings in the town.
"I hope that regular users of the library will keep up their interest in the service and find the other libraries, that are doing all they can to accommodate the extra users, equally as helpful and useful."