Back in the 18th century, America's book business called Philadelphia home.

Mathew Carey invented the American publishing house. Benjamin Franklin towered as America's printer. Charles Brockden Brown started the American novel on its way.

And then, history tells us, New York stole the book industry away, reducing Washington Square's "Publishers' Row" to memory lane.

Well, guess what? There's exactly one national magazine in the United States titled Book Business, explaining the mechanics of a rapidly changing $37.7 billion industry to an elite circulation of 12,100 subscribers.

It's not located at One Fifth Avenue or some similar chichi address in Manhattan. It's at 1500 Spring Garden St.

"When they say, 'Oh, are you in New York?'" confides editor-in-chief Noelle Skodzinski in her 12th-floor office, referring to industry sources, "and I say, 'No, Philadelphia,' they're kind of surprised, thinking that a magazine about publishing would ideally be located in New York.

"But it doesn't cause a problem, and we certainly don't get any flak from it."

"Lots of people probably don't realize we aren't in New York," jokes associate editor Matthew Steinmetz, 28. "Book Business - that brand - just screams 'New York.'

"People think you're there. 212? 215?? And, as you know, in this digital age, information transfers so fast, there's so much less face-to-face, it almost doesn't matter where you are."

But, of course, it does, in a city whose engagement with printing dates back to 1685.

It especially matters to Book Business' parent, the North American Publishing Company, which boasts 16 trade magazines. 2008 is its golden anniversary year.

The company began in 1958 when Irvin J. Borowski, who supported his family as a boy printer of 14 during the Depression, launched it with Printing Impressions, still the top magazine for commercial printers. (Borowski also founded the National Liberty Museum. His son Ned now runs North American.)

This year is likewise the 10th anniversary of the magazine launched by group publisher Mark Hertzog in 1998 as Book Tech.

"Printing and publishing is our core," says Hertzog, 54, a 20-year company veteran, in his corner office with a spectacular view. "We're the largest magazine publisher for the graphic arts industry."

Book Tech, he explains, originally focused on book manufacture and production. But in February 2006, Hertzog and Skodzinski re-branded it as Book Business (Frequency: 10 times a year), and broadened coverage to every aspect of the field except those ruled by its famous trade rival, Publishers Weekly: reviews and book chit-chat.

"We realized there was a niche in the market not being filled," says Hertzog. He saw a lack of "real information on technology and business practices, even as digital readers and print-on-demand (POD) shook up the field.

"There wasn't a need in the past," Hertzog surmises, "because book publishing was, and still is, such a steeped-in-tradition industry. . . . There are still typesetters in the book industry - they don't exist anywhere else."

Indeed, technology providers told him that if they could just get the ear of publishers, they could "help them leapfrog several generations of technology."

Hertzog says about 10,000 of BB's subscribers are book publishers, and 2,000 suppliers to the industry. Only 23 percent come from manufacturing and production, Book Tech's old core audience.

Skodzinski, 36, and managing editor Janet Spavlik, 34, agree that tech pressure on book publishing makes it an ideal time for the publication's re-branding. Article titles have included "E-Books: Have They Finally Arrived?"; "156 Tips for Improving Your Book Publishing Business"; and "Random House: The Best Book Publishing Company to Work For."

Skodzinski, Spavlik and Hertzog all point to print-on-demand as an instance of established industry habits under siege.

POD, Spavlik explains, means "the book is printed when the order is received." In old-fashioned publishing, the house guesses how many copies of a book it can sell, prints them, then prays.

Hertzog describes the system as "inefficient." Most book buyers have encountered two upshots of it: "out-of-print" books a publisher can no longer supply, and "remainders" - extra copies available cheap when a publisher overestimates demand.

According to Hertzog, POD may scuttle the very notion of "out-of-print." For a publisher with good POD, no book is ever out-of-print; it's just not printed yet. Similarly, remainders may disappear along with bad publisher guesses.

"It really has turned the model upside down," says Hertzog of POD. "You can basically publish a book for zero money, and not print one until you sell it . . . it can reduce inventory to zero."

Of course, some associations haven't faded. "There's definitely a stigma attached," says Spavlik. "When people hear POD, they do think of a lesser-quality book."

Skodzinski stresses that Book Business tells readers what they "need to know." For instance, as insiders wait to see whether Amazon's wireless book device, Kindle, catalyzes a mass flight from paper books, the industry faces the old Betamax problem: competing technological standards.

But Book Business will be reporting, Skodzinski advises, that the International Digital Publishing Forum has created an "ePub standard" and is "pushing the industry to adopt it." She says "that will really take a lot of pressure off publishers, because then they just have to make it available one way."

Given its national target audience, Book Business doesn't favor Philadelphia-area publishers. At BookExpo America, the annual book publishing convention held in late May, the magazine's staffers pitched the whole industry as it passed by.

But book publishers in Philadelphia, such as Quirk, provide camaraderie. "We went over to their offices and had lunch," says Skodzinski, "which is something we don't get to do all the time with publishers in N.Y."

Did we mention that the Book Business staff works very hard? They also put out a second publication, Publishing Executive, for magazine execs. And the company runs a yearly three-day March expo and conference in New York geared to high-level executives in both book and magazine publishing. It takes place in Manhattan.

The crew at 1500 Spring Garden are Philadelphia loyalists, but not crazy.

"Fifty percent of our attendees come from the greater New York area" says Hertzog.

That's OK, guys. New York is part of North America, even if it's not cool enough to host Book Business.