Jodi Picoult has written 22 books that have sold over 22 million copies. She is a literary superstar.From her writing post in Hanover, N.H., she often uses her status to help unknown authors find their toeholds — tweeting their maiden book launches and writing blurbs for their book jackets. But then along comes news like this week’s: a critically acclaimed but paltry-selling book by an unknown, first-time author was actually written by Harry Potter’s creator, J.K. Rowling. It immediately became a runaway bestseller. Rowling’s pseudonymous maneuver has reignited a debate in the writing community: In this age of e-books, self-publishing, and increasingly consolidated publishing houses, how does an unknown writer, even one with clear talent, break through?“The message is that it’s very hard to publish in this market as an unknown, which is a crying shame,” Picoult said.Publishing experts say the issue has long dogged new writers. Yet the problem now — or the challenge, as some euphemistically phrase it — can feel much more pronounced in a digital universe that has opened publishing to everyone.“The marketplace is so crowded now, so loud, that there’s even more reluctance by readers to reach for something new,” said Eve Bridburg, a literary agent and founder of Grub Street Inc., a Boston center for writers that teaches business and marketing skills.Just ask Abi Maxwell. She grew up in New Hampshire and studied fiction at the University of Montana. Last year, she was working as an assistant at the library in Gilford, in central New Hampshire, when she got great news. Her book, Lake People, had been selected for publication by Random House.The book garnered good reviews — Jane Smiley, writing in Harper’s, called its main character “beautifully precise.” Yet it did not reach bestseller lists. (It is 115,026 on Amazon’s print books bestseller list.)Rowling is such an exception in the publishing world, some say, that anything involving her seems only remotely connected to the realities with which other writers live. “It’s a fine thing,” said Arthur Golden, of Brookline, Mass., the best-selling author of Memoirs of a Geisha. “It’s only natural that people would want to read a book from an author like Rowling. It’s astonishing how popular she is.” And don’t forget, Rowling’s first Harry Potter book suffered multiple rejections before finding a publisher.