Foster's proposal injects false notes into a historic structure.

Even before Norman Foster presented his firm's scheme in late December to alter radically the New York Public Library's main branch, controversy swirled among scholars about plans to change Carrère & Hastings' 1897 Beaux-Arts masterpiece at 42nd Street and Fifth Avenue. Delay and secrecy in the design process exasperated the late Ada Louise Huxtable (page 26): in her last column in the Wall Street Journal, she said the library's proposal was “devised out of profound ignorance.” Now that Foster's plans are finally public, a rising tide of criticism may engulf a process seemingly arranged to avoid wider discussion.

This is a research library only; books do not circulate there. Before Foster showed his scheme, many scholars had objected to the proposal that called for moving millions of hard-to-find volumes off-site in order to consolidate two nearby libraries into the main branch for a lending facility. Architecturally, the core of the controversy is the removal of the core of the building: seven stories of book stacks stretching two city blocks. There the collection (open only to library staff) is stored in a dense hive of cast-iron shelves, which is hung from 1,300 thin steel columns.

Remarkably, this system also supports the floor of the magnificent Rose Main Reading Room above. These construction innovations were granted U.S. patents, and the library's spatial organization is equally ingenious. A lift rises through the tiers of shelves, delivering requested books to the center of the main reading room. That room itself, 297 by 78 feet, is a grandly proportioned space at the end of an almost operatic procession that visitors take via marble stairways ascending from the main entrance. On other levels, lavishly paneled rooms surround the stacks on three sides. The choreography of readers and books is central to the building's architectural experience.

Foster + Partners would consign the elegant iron-and-steel structure at the building's center to the ash heap of history. The scheme destroys the efficient, axial poetry of Carrère & Hastings, replacing the stacks with disconnected elements from elsewhere: the atmosphere reminds us of Foster's London Stansted Airport (1991), and the stair belongs in his ill-fated Harmon Hotel at Las Vegas's CityCenter (2010). The railings and soffits look like grilles on the latest Lincoln MKZ. The proposed reuse of cast-iron panels from the demolished stacks would lend an air of pathetic sentimentality to the mashup. The term “pastiche,” often used unfairly against those who modify buildings with stylistic sympathy, belongs here.

Unfortunately, the new functional arrangements are no better. A muddled, multilevel concourse would replace the stacks, and half of the books would move to existing below-grade storage. And how would they get to the reading room? Foster explained that they would travel on a conveyor “just like the baggage system in an airport.” Its route is absent from his drawings, but the books need to change directions at least five times (horizontally and vertically) as they zigzag around old masonry and new trusses. Library president and CEO Anthony Marx has suggested substituting a visible elevator shaft–another distraction. It is sad that the books are treated as baggage, and astonishing that book delivery, the crucial library function, has not yet been resolved.

The library has presented its architect with an impossible task: maintain the connection between glorious reading rooms and world-renowned research collections, but insert a sprawling digital-age facility between them. In consolidating the services of two outside libraries–which currently total 350,000 square feet–into the already busy 42nd Street library, the architects can add only 140,000 square feet (80,000 from Foster's plan, 60,000 from the new underground storage). These numbers need to be faced by library leaders; they want an expanded facility in a reduced floor area.

Marx invokes inevitable change as a justification for this project. But that logic lost us New York's Penn Station. In Paris, with the building of Dominique Perrault's Bibliothèque Nationale François Mitterrand in 1995, Labrouste's historic Bibliothèque Nationale was preserved; change can be bad or good. As the NYPL's renovation budget approaches $350 million, alternatives to Foster's scheme abound. It is not too late to change it. Rather than closing branches (and harvesting real-estate assets), officials should rebuild the nearby lending facility to accommodate greater public use and changing technology. This would save a treasured landmark from a second-class makeover and potentially add a first-class building to the world's greatest network of public libraries.

Charles D. Warren, a New York architect, is coauthor of Carrère & Hastings Architects (2006).