SAN FRANCISCO — Five years ago, Gary Frank decided to sell his bookstore here.

The Booksmith had built up a fine reputation over a quarter of a century, thanks to an impressive series of author appearances and a high-traffic location in the old hippie neighborhood of Haight-Ashbury.

Yet hardly anyone expressed interest. Frank was disappointed but not surprised.

"Maybe they saw the future," he said.

A Clean Well-Lighted Place for Books, open since 1982 near City Hall, sought a buyer, couldn't find one and closed last summer. Cody's Books shut its flagship Berkeley store after a half-century run. Black Oak Books closed one of its stores and is considering shutting the other two if a buyer can't be found. Numerous small new and secondhand stores have fallen with little fanfare.

The casualties are nationwide. Coliseum Books and Murder Ink in Manhattan shut down in recent weeks. Micawber Books in Princeton, N.J., couldn't make it. In Los Angeles, Dutton's 2-year-old outpost in Beverly Hills has closed, and the original Dutton's in Brentwood will be forced to shrink or relocate if the landlord carries through with plans to redevelop the site.

Rising rents and competition from the chains have imperiled independents for years, but San Francisco used to think it was immune. Cody's and other Bay Area stores helped spark the Beat movement, encouraged the counterculture, fueled the initial protests against the Vietnam War. In a region that sees itself as smart and civilized, bookshops were things to be cherished.

No longer, apparently. The stores that are still in business feel compelled to underline that fact.

"Rare but Not Extinct," one proclaimed in a holiday ad. Another, announcing a special sale in a leaflet, felt the need to emphasize, "We're not going out of business."

What's undermining the stores is a massive shift in buying habits brought about by the Internet. Ordering from Amazon.com, Frank said, has almost become the generic term for book buying.

Technology changes behavior, which reshapes the physical landscape. The era of repertory movie houses playing "Casablanca" and "High Noon" ended with the VCR. The telephone booth was replaced by the pager, which was made obsolete by the cell phone. And the newspaper is under siege by the Internet's ability to recombine and distribute news without leaving ink on your hands.

"The bookstore as we know it is in dire straits," said Lewis Buzbee, a novelist who spent many years working in the local shops.

That sense of peril is doubtless one reason "The Yellow-Lighted Bookshop," Buzbee's loving memoir of his time as a clerk in the Bay Area interspersed with a history of the bookselling trade, has become a small but genuine hit. It's just gone into its fourth printing, with enthusiastic crowds flocking to the writer's appearances.

A good bookstore, he notes, is unlike any other retail space. Where else can you linger, sample the merchandise and then casually reject it if not quite right? Your local pizzeria would frown on such behavior. In a culture that worships money, bookstores are one of the few commercial institutions where cost doesn't trump all other considerations. Massive bestsellers share shelf space with the most obscure tomes.

Buzbee exalts a place where time seems to slow but hours can disappear in an instant, where browsers coexist in a companionable solitude, where a chance encounter with the exact right volume might create an explosion in your head.

"Not only could your world change, but the rest of the world could change," he told an audience at the City Lights bookstore in North Beach.

It was a message that Kim Webster, an apartment concierge, heard and found eloquent. Buzbee captured, she said, "the essence, the nirvana feeling, the power of the written word."

But she didn't buy his $17 volume that night. Maybe later, she said, maybe from her local chain superstore.

And if she missed it there, the Internet is an emporium that never closes.

This is the paradox of modern bookselling.

It's hard for any single used bookstore to compete, just as it's impossible for any shop carrying new books to rival the electronic plenitude of Amazon. Because the Internet retailer doesn't have to pay rent for display space or charge sales tax, its books are almost invariably cheaper.

"I'd be really hard pressed to come up with a single social or demographic trend that is in favor of bookstores," said Tom Haydon, whose Wessex Books in Menlo Park was for decades the best secondhand store in the 50-mile stretch between San Francisco and San Jose.

Unable to find a buyer who would pay even a minimal price for the stock, Haydon closed in June 2005.

"It's a lost cause," he said.

"The purpose of a business is to satisfy the needs and wants of a customer," said Albert Greco, a book industry consultant. "That's what the online world has done."

Maybe that's why passions among literary folk now seem so muted.

When sliding sales forced Cody's to close its store next to the University of California, Berkeley campus, the poet Ron Silliman wrote on his blog that it was once the anchor of "the best book-buying block in North America."

But in the discussion that followed, the attitude was one of resignation if not indifference.

"Why would anyone want to perpetuate small independents by paying higher prices?" wondered Curtis Faville, a poet who sells rare books on the Internet. "Most of these proud little independents were poorly run anyway."

Less harshly, Silliman suggested in an e-mail that "we're simultaneously caught in the wonder of the new and true mourning for the losses of the old."