Here is what we do know:

The new Harry Potter book, the fourth volume in the super-selling series by British writer J.K. Rowling, is the biggest publishing event in American history.

Scholastic is cranking out 3.8 million copies right off the bat, the largest first printing of any book ever, said Judy Corman of the publishing company. As a yardstick: A John Grisham novel usually has a measly first printing of 2.5 million or so.

A significant portion of the entire population of prepubescent Washington is going to be up past its collective bedtime late next week. Harry Potter IV – as it's right now being called – will be unleashed at a blink after midnight on Saturday, July 8. All sorts of bookstores throughout the English-speaking world are staying open into the witching hours to deal with the expected crush.

Nearly 30 million copies of the three other Harry Potter books are already in print. They have been published in more than two dozen languages. That's a better per-book average worldwide than Dr. Seuss.

Harry Potter IV will be 752 pages, according to advance publicity – longer than "The Canterbury Tales," "Bonfire of the Vanities" or the Koran.

The actor reading the audio version will mimic more than 125 voices.

The Fairfax County Public Library has ordered 300 copies of the hardback and 42 of the audio version to try to appease demand.

The new book will retail for $25.95. The last one was listed at $19.95.

Harry will be older. He ages one year in each book. This time around, he's 14.

The book has rocketed to the top of online bestseller lists around the world.

"The logistics of getting this book out are very buttoned up and very concise," Corman said. "The title and contents are being kept secret because the author wants the children to savor the book."

Here, then, is what we don't know:

The title. For a while it was rumored to be "Harry Potter and the Doomspell Tournament." That may have changed.

Who dies in the novel. Rowling has said that her books would become darker and darker – she's planning seven in all – and that more characters may buy the farm in No. 4. In Volume 1, "Harry Potter and the Sorcerer's Stone," we learned that Harry's parents were murdered.

And perhaps the biggest unknown of all: Will kids really read a 752-page tome?

Kyle Dodd of McLean said he's ready for the challenge. Kyle, 12, who will be in the seventh grade at Flint Hill Middle School next year, was one of those boys who just couldn't wait for Volume 3, "Harry Potter and the Prisoner of Azkaban." He knows the new book will be lengthy, and he's prepared for some heavy – literally – summer reading.

"I think it will take a long time to read," Kyle said. Until now the longest book he has read is Volume 3, which is 435 pages. He plans to enjoy the new book during a couple of family vacations.

Kyle's kid brother, Jake, 10, is also waiting for the new Harry with bated breath. Jake's glad the book is longer. "It's going to keep me busy for a little bit," he said.

"I haven't decided whether to buy one or two," said the boys' mother, Karen Dodd. If she can't find it cheap enough, she added, "I'll just be buying one."

Brian Foy, 10, of Vienna, said he's undaunted by the length of the fourth book. "Yeah, it seems like a lot for a kids' book," he admitted. "But in our house, we read it as a family, so it won't take as long."

Fascinating, really. The Harry Potter books are already legendary for attracting non-reading children, especially young boys. Is Rowling on a roll? Is she singlehandedly leading a new generation to the extreme pleasures of total immersion in a book? Will today's Potter-lovers be toasting Tolstoy tomorrow? Marching through "Middlemarch"? Zealous for Zola? Delighting in Dante and Dickens and Dostoevsky?

Or is she pushing her luck by writing such an epic adventure? Can she continue to overcome nanosecond attention spans and Dreamcast mentalities? Will she lose readers in her labyrinthine world, like so many people with a penchant for Thomas Pynchon who lapped up the 152-page "The Crying of Lot 49" but got hopelessly lost in the 784-page "Gravity's Rainbow"?

Brian's mom isn't too sure about the longish novel. "Why did she do that?" Catherine Foy asked. "She must have gotten carried away."

Brian, his mother explained, "has been waiting for this book to come out. "He's been anxious to get back into reading."

Harry Potter, in case you've been a cast member of "Survivor" for the past year or so, is a student at Hogwarts School of Witchcraft and Wizardry.

He studies how to make potions, cast spells and get along with folks who aren't witches. He has some fanciful friends, such as the heroic Hermione. And some dastardly enemies, such as Lord Voldemort and Draco Malfoy. He engages in a strange competition called Quidditch, which is played while riding a broom.

For some, Rowling – who stands to make more than $10 million just on the first-edition hardback sales of Harry IV – has been a category-killer. In the way that Tiger Woods has reshaped professional golf, Rowling has altered reading habits. Not bad for a single mother from Edinburgh who in the mid-1990s had never published a book and was on the dole.

Catherine Foy explained that Brian has had trouble delving into other books besides Rowling's phantasmagoric novels. "That'll be our summer reading," she said.

The Foys, like more than 232,332 other folks, have already ordered the book from Amazon.com. The online behemoth is keeping a Daily Muggle Count, that is, the number of non-magical humans who are ordering the book ahead of time. The first 250,000 who reserved the book and asked for standard shipping were offered Saturday delivery by Federal Express at no extra cost if they lived in urban areas.

In the Washington area, lots of bookstores are battening down the hatches for Pottermania. Booksellers have had to sign affidavits promising not to release the book too early. Barnes & Noble stores will stay open until 1 a.m. Saturday morning, July 8, and the books will go on sale one minute after midnight. At the Bethesda shop, special activities will include magic tricks, a trivia contest, a modified Quidditch game (normal Earth-gravity rules), free coffee for the adults and other giveaways.

Many other chain and independent bookstores are also staying open late.

Some booksellers are anticipating a large run on the books over the weekend. At the B. Dalton store on Wilson Boulevard in Arlington, employees will don capes and hats on Saturday morning and pass out Harry Potter glasses.

So how big is Harry Potter IV? You'll soon be seeing the books everywhere. Not just in bookstores, but in Price Clubs and supermarkets. Toy stores are also getting in on the act. When Rowling was in town last fall, she signed copies for several hundred people at Toys Etc. in Potomac. This time around, the shop has ordered about 600 books.

Toys Etc. general manager Carlos Aulestia said his store will close, as usual, at 8 p.m. on Friday night but will reopen at 12:01 Saturday morning. The store has taken orders for more than 350 books already and is expecting to hawk an additional 100 in the witching hour.

Child's Play, a toy store on Connecticut Avenue NW, has presold more than 200 books. To handle the swell, the store is opening Saturday at 8 a.m., "a more child-friendly time than 12:01," said Deborah Johnson, a bookseller for the store.

Winds from the Harrycane are blowing even through grown-up bookstores. "We've tried to ignore it, but we can't," said Philip Levy, owner of the oh-so-serious Bridge Street Books in Georgetown. "We're not the kind of bookstore that pays attention to trends. But this is so big we've had to pay attention."

Levy explained, "We're an intellectual bookstore, with two bookshelves of kids' books. But it's the best-selling children's book we've ever had."

Levy, whose store will celebrate its 20th anniversary on Tuesday, is making special plans for the Harry Potter craze. "I've ordered about 10 copies," he said. "That's a lot for us."

In Harry Potter IV, Rowling revealed in an online interview, the reader will discover that there are other wizardry schools such as Hogwarts, and Harry plays in the Quidditch World Cup.

Potter knows how to play Quidditch; Scholastic knows how to sell children's books.

"They've always been a tremendous market force in children's publishing," said Stuart Applebaum of Random House. "We have always seen Scholastic as our principal competitor."

Applebaum was quick to point out that the Harry Potter craze has been tremendous for the whole publishing industry.

"When you have that kind of excitement about a book that is so ubiquitous and all-consuming," Applebaum said, "it gets everybody revved up about books. That enthusiasm is bound to spill over."

He likens the effect to a hit movie playing at a multiplex cinema.

For that specific effect, folks will have to wait awhile. The first Harry Potter movie, based on Volume 1, isn't scheduled for release until the fall of 2001. Warner Bros. is making the movie and owns the merchandising rights to all of the Harry Potter gimcracks and gewgaws that will soon be clogging up stores.

Harry Potter IV "is a traffic-builder," Applebaum said, which is cool relief to publishers and booksellers during the dog days of summer.

Applebaum added that Random House/Listening Library will release 200,000 copies of the Harry Potter IV audio book, read by Jim Dale – who was the voice of the first three volumes – on July 8. It will run more than 20 hours. There are nearly 1 million audio versions of the first three books in print.

At the Fairfax County Public Library, more than 800 folks have signed up – many via the Web site – to borrow a copy of Harry Potter IV. Library spokeswoman Lois Kirkpatrick said she's never seen such a rush.

Scholastic, Barnes & Noble and other companies are running contests built around the book's release.

Though Rowling is not slated to come to the United States this time, she will be promoting the book in England. On July 8 she's going to ride a special steam-driven train, called the Hogwarts Express, from London to Edinburgh. Tickets for the event have been hidden throughout bookstores in England and Scotland.

On Web sites, Harry Potter fans' interest is reaching a fever pitch. Rumors ricochet across the Internet: Ron is going to die, no he's not, but someone else will. There will be a nasty character named Icicle. There are even speculations about future books. Rowling has remained pretty tight-lipped about what will happen. She has said that the last book will be another long one and that the last word of the last chapter of the last book will be "scar."

But that is several years – and millions and millions of copies – in the future. For now, eager readers are still trying to guess what Harry Potter IV will be about.

"Maybe he might get, like, a girlfriend," predicted Brian Foy. "Maybe Hermione."

Sure enough, Rowling has told folks that Harry does find a girlfriend in the coming novel, but – and, shhh! don't tell Brian – it's not Hermione.