“This is a stake in the ground for the future of our great research library,” Anthony W. Marx, the library’s president and chief executive, said in an interview, speaking of the plan as a whole.
The master plan is the latest, and close to final, stage of what the library calls its “pivot” away from its earlier, controversial Central Library Plan. That proposal, which would have involved selling the Mid-Manhattan branch across Fifth Avenue and constructing a new circulating library (designed by the British architect Norman Foster) inside the Schwarzman building, drew substantial criticism and was abandoned in 2014. Instead, the library is currently renovating the Mid-Manhattan branch, which is to reopen in 2020.
Credit Mecanoo with Beyer Blinder Belle
Mr. Marx said that the new plan accomplished many of the objectives of the earlier one, including making the Schwarzman building more welcoming to a broader range of users.
“We’ve found a way to achieve what we need in more manageable chunks that are also more respectful of the incredible architecture of this building,” he said.
Francine Houben, the creative director and founding partner of Mecanoo, who is leading the project, said the plan preserved the “logic” of the 1911 Carrère & Hastings design, while easing congestion and navigation for visitors, who number about three million a year.
“The building’s floor plan is very simple,” Ms. Houben said. “But it’s not easy to find your way around here.”
Over all, there will clearer separation of functions, with the ground floor focused on noisier, more public activities, while the upper floors cater to more serious researchers, who will have roughly 250 more seats available to them.
The $317 million price tag includes $144 million of infrastructure improvements and other work done in the building since 2006. (The building will remain open throughout construction.)
The most visible changes will be on the ground floor. Inside the grand Fifth Avenue entrance, to the right of Astor Hall, an elegant balconied space now used for map storage will be restored and opened up, most likely for a cafe.
Straight ahead will be what the library calls a “necklace” of exhibition spaces. Gottesman Hall, long used for temporary exhibitions, will house a permanent rotating “treasures” exhibition, drawn from the more than 50 million books, manuscripts, artworks and other items in the research collections.
There will also be two smaller exhibition spaces, including one in the location of the current gift shop, which will move to a larger space closer to 40th Street. (The current Children’s Center, near the 42nd Street entrance, will move to the Mid-Manhattan Library, whose renovation was also designed by Mecanoo with Beyer Blinder Belle.)
Credit Mecanoo with Beyer Blinder Belle
The new 40th Street entrance, which comes with a new plaza, will be created by making a minimally invasive cut into the library’s facade, around two existing windows. (It is the only major aspect of the plan that will require approval from the Landmarks Preservation Commission, the library said.)
That entrance will lead to the new Center for Research and Learning, where high school and college students can be introduced to working with primary-source collections.
“We want to get them excited about research, so they understand it isn’t simply about Googling something,” William Kelly, the director of research libraries, said.
The stack study, which the library said would take about six months and involve consultation with people inside and outside the library, reopens an issue that has been a continuing source of resentment among some researchers and preservationists, who insist that the space should be a home for books. (Most of the roughly 2.5 million volumes formerly in the stacks are now housed in two floors of modern, high-density storage space under Bryant Park.)
Mr. Kelly, who arrived at the library in 2015, declined to be specific about what unmet needs the vast space might address, or how quickly any plans might be carried out.
Mr. Kelly did allow that the library “would continue to need space for books,” which it acquires at a rate of about 50,000 a year. But he said the idea was to be “completely open-minded.”
“We’ve got 175,000 square feet,” he said. “We should be able to do a lot of different things.”