His fortune, which was valued at $400 million when he died in 1919, paid for more than 2,500 branches. Carnegie was a staunch believer in meritocracy. He was convinced that anyone, no matter how poor, could be lifted up by knowledge, and he insisted that his libraries express that in their architecture.

If you're not met at the entrance by an impressive staircase and a mighty portal of classical columns, chances are the building isn't a Carnegie. In many neighborhoods, his libraries are still the most dignified buildings residents ever encounter. Walking through those heavy doors is the first step in the hard passage to a middle-class life.

Philadelphia, which created the nation's first public-library system, had the good fortune to receive 25 of Carnegie's libraries. But if Mayor Nutter goes through with his crisis plan to shrink the library system by 11 branches, the city will lose four representatives of its original Carnegie legacy.

What will happen to Carnegie's four temples of knowledge is anyone's guess. Some might be used for other city purposes. Some might be sold, assuming the Carnegie deed permits the transfer. But others could be left to sit vacant, transformed into temples of gloom, monuments to opportunities lost.

It's not just books that people are losing. Carnegie libraries - indeed, all library branches - are more than quaint storage units for the musty old media. They are community hubs around which whole neighborhoods revolve.

The Philadelphia branches, which were all freshly renovated during the John Street years, serve as meeting halls for neighborhood groups and as oases of quiet for kids seeking to escape noisy rowhouses. Preschoolers learn to enjoy hearing words read aloud as they sit in a carpeted corner for story time. Most important, libraries provide a lifeline to the increasingly wired modern world for the legions of Philadelphians without computers.

The mayor says the library buildings designated for permanent closure were chosen after careful deliberation. Because the population has shrunk, the city now operates more branches per capita than other large cities. Even after those 11 are eliminated, Nutter says, no Philadelphian will live more than two miles from a library. He has promised to send bookmobiles into library-less neighborhoods.

In some ways, you can't help but admire Nutter's systematic approach. Philadelphia's government does need to be right-sized to reflect a smaller population. The depth of the current budget crisis requires tough decisions. Nutter made them unsentimentally.

Too unsentimentally, perhaps, when it comes to libraries.

Statistics are the language of bureaucrats, not the language of real life. So while it is undeniable that Philadelphia supports more than its statistical share of branches, it is also true that it has a larger proportion of poor families than most big cities. Many of their kids go to public schools that have no libraries.

The poor, as Carnegie understood, are destined to remain poor unless they have access to information. In 2008, that information is digital. Yet, in Philadelphia, barely half the households have computers and Internet access, compared with 77 percent nationally, according to information compiled by the Pew Internet & American Life Project.

The lack of daily experience with computers is one more way that the city's poor young people are tethered to a life of low expectations. It's not just that their more-affluent peers save time using computers for homework. They also incorporate the Internet into their lives in a myriad of ways, from social networking, to making PowerPoints, to downloading the latest video.

Without the same Internet fluency, Philadelphia's youth will be about as competitive as villagers in the Amazon. You can hardly apply for a job today except online.

Defining poverty has always been difficult. Half the branches slated for closing are in neighborhoods where library statistics show more than 20 percent live below the official poverty line. But when I visited the Carnegie library in Holmesburg, where a mere 11 percent of families are officially poor, not one child I interviewed had a computer at home.

Vincent Yarnell, a fifth grader at the J.H. Brown school, told me he spends every afternoon at the branch, a stately brick structure, doing homework, reading Charlie Bone novels, and researching school assignments on the library's computers. Because he lives a block away, he often returns after dinner.

Vincent doesn't own a computer, nor, he says, do any of his friends. But he impressed his teacher recently when he printed out a portrait of the 18th-century African American astronomer Benjamin Banneker for a project. Once Holmesburg closes, the nearest branch will be Tacony. No way will Vincent's parents let him take the bus there on his own.

Several hundred Holmesburg residents turned out Monday to protest the library's closing. But they weren't looking for special treatment from the city. Instead, they vowed to join the Friends of the Free Library's campaign to raise privately the $8 million needed to keep the 11 branches open. The effort echoes the Carnegie creed: He demanded that residents buy the land to qualify for one of his libraries. Of course, the Friends' effort is an Internet campaign (www.libraryfriends.info).

You would think the mayor would welcome such citizen initiative. But a city spokesman told me that the Nutter administration intends to refuse the money. "We think a smaller city library system will be a stronger system," he explained.

Instead of finding fault in Philadelphia's large collection of neighborhood branches, the administration ought be crowing about being at the top of this particular statistical heap. You can bet Andrew Carnegie would be.