When J.K. Rowling first met her agent, Christopher Little, over a lunch in London in 1995, he felt it only right to sound a cautionary note: "Now, you do realize, you will never make a fortune out of writing children's books?" Three years later, Rowling's first book, published in the U.S. as Harry Potter and the Sorcerer's Stone (Scholastic/Arthur A. Levine, September), has leapt to the top of the bestseller charts, both here and in the author's native UK; racked up major prizes, from the Smarties Prize to the British Book Award; earned a six-figure film deal with Warner Bros.; and brought Rowling so much fan mail that she is hiring a full-time secretary, and such an avalanche of personal publicity that the British tabloid The Sun tried (in vain) to buy rights to her life story.

The story behind Harry Potter might rival the book itself in its fairy-tale proportions and its sense of deserts justly delivered. Harry is 11, an orphan being grudgingly raised by his despicable Aunt Petunia and Uncle Vernon, when he is contacted by the Hogwarts School of Witchcraft and Wizardry and offered a place in the entering class. Until then he has had no idea that an entire world of witchery surreptitiously coexists within ordinary society -- and even less idea that in that wizardly world he is something of a legend. Rowling's extraordinary combination of fantasy, humor and high adventure has prompted many reviewers to invoke Roald Dahl ("But not as dark!" emends one Amazon.com enthusiast).

Rowling, now 33, began Harry Potter back in 1990. She had written and put aside two adult novels that were, in her own estimation, unpublishable, when, during a lengthy train trip, she got the idea for Harry Potter. "It just came: bang!" she says. From the beginning, she conceived of it as a seven-volume series, "because I decided that it would take seven years, from the ages of 11 to 17, inclusive, to train as a wizard, and each of the books would deal with a year of Harry's life at Hogwarts."

To make sure she knew how her fictional world worked, she created "loads and loads" of notes, setting out wizard laws, history, etc. She essentially mapped out all seven novels, laying the foundation from the start; she has even written the last chapter of the final book, "to remind myself where I'm going." However clear-sighted her plotting, Rowling needed every scrap of will power to bring Harry into being. Over the next four years, she moved to Portugal, held a full-time job as a teacher of English, got married, gave birth, ended her marriage and moved to Edinburgh with a 5-month-old daughter to raise by herself -- and the first three chapters of Harry Potter. Lacking child care and unable to take a job without it, she went on public assistance. In many ways, she says, it was one of the lowest points of her life.

To be sure her daughter would nap long enough to give her time to write, Rowling would lull her to sleep in a stroller. "Then I would run -- literally, as I couldn't afford to waste a minute -- to the nearest cafe. By trial and error I had found the ones that would allow me to sit with her for an hour and a half [the typical length of a nap] with one cup of coffee, which was all I could afford."

In the evenings, when the baby went to bed, Rowling would surmount her own exhaustion and work several hours more until the baby woke up for her nightly feeding. "That's the bit I'm proudest of," she says, "the effort of will involved. It was proof positive of how much I wanted to write Harry." She found Christopher Little in 1995, in the Writers' & Artists' Yearbook (the UK equivalent of Literary Market Place). He was the second agent to see her book -- the first had sent it back "virtually by return of post," with a form letter. In the year that followed, three publishers declined the book on the grounds that it was too long for children. But the fourth, Bloomsbury, accepted it immediately, and it was Bloomsbury that tipped off Scholastic's Arthur Levine during the 1997 Bologna Book Fair and arranged for Little, who controlled the rights, to send it to him.

Levine purchased American rights for a jaw-dropping $105,000, causing a splash in the British press, which widely reported it as the highest sum paid for a first children's novel (the sale was also widely reported as topping 100,000 pounds, not dollars). Rowling became known for her rags-to-riches career, and the publicity escalated as Harry Potter and the Philosopher's Stone, as the book is titled in Britain, went on to win prize after prize.

So popular have Harry Potter and its author become that when the sequel, Harry Potter and the Chamber of Secrets, appeared in the UK this past July, it debuted as the top-selling book in the country, beating out Jeffrey Archer and John Grisham. (Scholastic/Levine will bring it out in the U.S. in September 1999.) To capitalize on the unexpected crossover phenomenon, Bloomsbury has published a second edition of Harry Potter and the Philosopher's Stone with a cover designed to attract adults.

A crossover market seems to be shaping up in the U.S. as well. A month after pub date, Harry Potter had carved out the top spot on PW's children's fiction bestseller list; in mid-December it was #2 on Amazon.com's overall list. Scholastic has been back to press seven times, each time with larger print runs, according to Levine, for a total in-print figure of more than 190,000 copies.

Rowling, having delivered the third Harry Potter book to Bloomsbury and now working on the fourth, says she didn't consider her possible audience when she conceived the series. "What excited me was how much I would enjoy writing [Harry Potter]. I never thought about writing for children -- children's books chose me."