ince September, the nation's second-largest bookseller, Borders Group, has quietly been conducting an experiment in six Philadelphia-area stores, not as a bookseller, but as a publisher.

"It's easy to publish your own book!" the "Borders Personal Publishing" leaflets proclaim. Pay $4.99. Take home a kit. Send in your manuscript and $199. A month or so later, presto. Ten paperback copies of your novel, memoir or cookbook arrive.

Fork over $499, and you can get the upscale "Professional Publication" option. Your book gets an International Standard Book Number, publishing's equivalent of an ID number and is made available on Borders.com, and the Philadelphia store makes space on its shelves for five copies.

Borders is the latest traditional bookseller or publisher to branch into self-publishing using print-on-demand or P.O.D. technology. P.O.D., inheritor of the vanity press and survivor of the dot-com implosion, makes it feasible - technologically and economically - to produce one copy of a book.

Unlike e-books, which also appeared in the late 1990's, P.O.D. self-publishing has developed into a real business, attracting involvement from the likes of Random House, Barnes & Noble and now Borders.

"We wanted to learn about the market," said Phil Ollila, Borders's vice president for book marketing, in explaining the chain's experiment. The company approached Xlibris, based in Philadelphia, one of the big three of P.O.D. self-publishing, together with 1stBooks and iUniverse, all formed in the late 1990's. Xlibris is 49 percent owned by Random House Ventures; 1stBooks, based in Bloomington, Ind., is privately held. Barnes & Noble owns 25 percent of iUniverse, based in Lincoln, Neb., and Warburg Pincus holds the other 75 percent.

These more established publishing businesses decided to invest in P.O.D. to diversify and expand their role. "There was the farm team idea - could we find authors?" said Richard Sarnoff, the president of Random House Ventures. "As niches get smaller, is it a model for the future?"

Steve Riggio, the chief executive of Barnes & Noble, said, "Self-publishing, previously viewed as a means of last resort, is increasingly seen as a first step."

Thoughts of the future aside, there is the matter of the current market. The three companies combined have produced more than 45,000 titles so far, at a cost to authors of from $459 to $1,900. (Some Borders packages are more limited, and thus cheaper.)

The real challenge is not to produce books, it is to achieve all the goals of publishing - to get the books edited, distributed, noticed and, above all, bought. That is no easy feat: in the United States, 150,000-160,000 new titles were published last year, according to R.R. Bowker's Books in Print. On average, the P.O.D. titles sell just 150 to 175 copies, the companies say. Many authors are happy to pay for 50 or 100 copies of their magnum opus to give or sell to family, friends and business contacts. Others, though, confuse production with publication and end up disillusioned.

To address that problem, all three companies emphasize marketing, promotion and publicity options, either bundled into the packages or sold separately as add-ons.

The majority of sales of self-published books occurs online. According to Susan Driscoll, iUniverse chief executive, 40 percent are sold directly to authors and the other 60 percent move through retail channels. John Feldcamp, the chief executive of Xlibris, like his colleagues, maintains that book sales "are colossally important; they are more profitable than the services." But the add-ons generate cash and pull in authors.

At iUniverse, the "Star" program is another important hook. If a title sells more than 500 copies its first year, the company may invest in marketing the book and invite the author to become a Star.

But of iUniverse's 17,000 published titles, the authors of only 84 have been chosen as Stars, and only a half-dozen have made it to Barnes & Noble store shelves.

An exceptional seller is a book like "The Sweater Letter,'' a true-crime story from iUniverse, which has sold about 10,000 copies. Its author, Dave Distel, who worked for The Los Angeles Times for 23 years, said he "didn't want to go through the song and dance" of finding an agent and publisher. But he said he was "unaware of the stigma" associated with self-publishing and did not understand that booksellers expect discounts and also expect to return unsold copies. iUniverse worked with him, and Mr. Distel said he was satisfied.

The fundamental difference between P.O.D. publishers and old-style vanity and subsidy presses is cost. Traditional vanity houses like the 55-year-old Vantage Press charge on average $8,000 to $10,000 - and sometimes as much as $50,000 - to produce copies that an author then owns. Subsidy publishers own the copies, but give the author a "royalty," actually a rebate, for each one sold.

Last fall, Patty Yoder, who lives on a Vermont sheep farm, paid Ivy House Publishing $27,900 to subsidize 2,000 color copies of "The Alphabet of Sheep,'' a 64-page hardcover with her memories and her 26 handmade hooked rugs depicted inside. "For years I kept running into a wall looking for an agent or publisher," Ms. Yoder said.

It is unlikely, however, that Ms. Yoder will recoup her investment in the book. For selling about 800 copies of the book herself, she received only about $7,000 in royalties.

Occasionally, a P.O.D. or other self-published title is discovered by a traditional house. Philip Simmons, dying of Lou Gehrig's disease, wanted to see his words in print quickly. He turned to Xlibris, which published several thousand copies of his memoir, "Learning to Fall: The Blessings of an Imperfect Life,'' in 2000. The book was received to critical acclaim, and was republished by Bantam Books in 2002. Mr. Simmons died last July.

Mr. Feldcamp said that conventional publishers had acquired about 20 Xlibris titles. An iUniverse author, Laurie Notaro, even made the paperback best-seller list with "The Idiot Girls' Action-Adventure Club," and received a two-book contract from Random House.

But these are far removed from the experiences of most authors. The odds are stacked against such books reaching the shelves of the chains or the attention of news media. Mr. Riggio of Barnes & Noble cautions, "Writers should have no delusions it's a fast way to get into bookstores."

Whatever method of self-publishing an author chooses, one factor is the same: the author is the only one driving the sales. "The bottom line," as Ms. Yoder has learned, "is promoting yourself. When push comes to shove, it's your money."