FINAL CHAPTER

These are the sums of all fears for Harry Potter fans: 3,677 days, 4,195 pages and 19.7 pounds. They are harsh reminders that all good things – including books – must finally come to an end. In the case of the literary juggernaut that is Harry Potter, that end is July 21, when “Harry Potter and the Deathly Hallows,” the seventh and final installment of J.K. Rowling’s mind-numbingly successful book series about a boy wizard growing into manhood, is released to the public. (Rowling has stated time and again that the Harry Potter series ends with book seven.)

The date will mark a decade (3,677 days to be exact) since the British publication of Rowling’s first book in the series, “Harry Potter and the Philosopher’s Stone,” which was published 14 months later in the United States as “Harry Potter and the Sorcerer’s Stone.”

The completion of the series, which will total 4,195 pages and come in at nearly 20 pounds, presents the publishing and book-selling industries, not to mention the reading public, with a unique situation.

Never before has a book series been so popular or more financially successful. Worldwide, there are 325 million copies of the previous six Harry Potter books. The first four Harry Potter movies (a fifth, “Harry Potter and the Order of the Phoenix,” is scheduled to open July 13) have grossed more than $3.5 billion worldwide, and Rowling is the first-ever billionaire author.

So what happens when the party’s over?

For Bloomsbury, the small British publishing house that launched Harry Potter, and Scholastic, the sole U.S. publisher, the final book means the largest cash cow in the history of publishing will stop delivering fresh material.

For the major book chains, such as Borders and Barnes & Noble, which have feasted on the Harry Potter books, it may mean an end to double-digit increases in children’s book sales every year.

And for readers – well, it will be like losing a whole set of cherished friends forever.

Even so, for most fans of Harry, the countdown to book seven’s release has been a time of dizzying excitement, not dread.

“I know just as many adults looking forward to this book as children,” said Kathleen Horning, president of the Association for Library Service to Children, a division of the American Library Association. “So many people all over the world have the same reading experience in common. … There are so many different kinds of readers the books appeal to – something which is hard for any children’s book to do – those who are interested in adventure, mystery, fantasy, school, sports, humor.”

The only known facts about book seven are these:

•Harry and his mates, Ron Weasley and Hermione Granger, should be entering their seventh year at Hogwarts School of Witchcraft and Wizardry, but it is uncertain whether the school will reopen and whether the three will return even if it does. They are now allowed to perform magic outside of school and are eligible to obtain Apparition licenses.

•Two characters will die.

•Scholastic is set to release 12 million first-print copies of “Deathly Hallows.”

•There has been a 547 percent increase in orders of book seven compared with book six, on amazon.com.

On June 26, 1997, when “Harry Potter and the Philosopher’s Stone” was published in Great Britain, no one could have known – least of all Rowling, then struggling to pay the rent – that the 10-year-old fictional hero who lived under the stairs of his all-too-human relatives would usher in an unprecedented era in book publishing.

The origins of the Harry Potter series have become the stuff of legend. Harry was hatched in Rowling’s imagination on a train ride from Manchester to London in 1990. She wrote much of the book, longhand, at Nicolson’s cafe, now a Chinese restaurant, in Edinburgh, Scotland, where she moved with her infant daughter shortly after a divorce. Too poor to make a copy of the manuscript, she typed two and sent them out. Several rejections later, Bloomsbury bought the book for the equivalent of $4,000. Arthur Levine, an editor with his own imprint at Scholastic, read the manuscript on a plane trip from New York City to Bologna, Italy, and eventually outbid seven other companies for the U.S. rights.

The initial U.S. printing of “Harry Potter and the Sorcerer’s Stone” in 1998 was a mere 50,000 copies. By the time the sixth book was released in July 2005, Scholastic printed 10.8 million. Today, only the Bible and “Quotations from Chairman Mao” have more copies in print than the Harry Potter books.

“We’re very, very excited about book seven,” said Kyl Good, a spokesperson for Scholastic. “This is going to be the biggest publishing event ever, and we get to bring this to millions of readers.”

Virtually no corner of the world has been untouched by “Pottermonium.” The series has been translated into 64 languages, including one dead one (Latin), and the name Harry Potter is familiar to hundreds of millions, whether they are Lithuanian (Haris Poteris), Chinese (Ha li po te) or Arabic (Hari Butar). Even parodies of the Harry Potter series have been translated into Belarusian and Hungarian.

In the hours after the Feb. 1 announcement of book seven’s publication date, “Harry Potter and the Deathly Hallows” was No. 1 with a bullet on both Amazon and Barnes & Noble Web sites. To date, at least a half-million copies already have been ordered on amazon.com (where the book is selling at a 46 percent reduced rate of $18.89 instead of the list price of $34.95), including one by the librarian at the military prison camp at Guantanamo Bay, Cuba.

The biggest winners in the financial windfall that is Harry Potter, other than Rowling, have been Bloomsbury and Scholastic. When the title of the seventh book was announced at the end of December 2006, shares of Scholastic gained more than 2 percent in a single day. And earlier this year, when Bloomsbury revealed the publication date – on the London Stock Exchange, to boot – its own shares rose 2.2 percent.

But as Harry goes, so goes the publishing industry. At the end of the fiscal calendar for 2005, Scholastic, which did not publish a Harry Potter title that year, experienced a 15 percent drop in sales in its children’s book division.

Rowling and her publishers, as well as the movie industry and the manufacturers of literally thousands of items of merchandise, are not the only beneficiaries of Harry Potter’s financial prowess.

The series also has spawned books about the series, including “What Will Happen in Harry Potter 7,” co-authored by 20-year-old Emerson Spartz, who founded one of the most popular Harry Potter Web sites, www.mugglenet.com.

“I just learned that Wal-Mart has ordered 30,000 copies of the book,” Spartz said earlier this month. “And it’s on the New York Times children’s books best-seller list,” added the sophomore business major at the University of Notre Dame.

After an initial printing of just 9,000, there are now 270,000 copies of “What Will Happen in Harry Potter 7” in print, according to Spartz.

Like many other teens and young adults, Spartz has grown up with the characters in the books, which is one of the special features of the series.

“Harry is the first character in children’s literature who ages,” said Horning, of the American Library Association. “Nancy Drew, poor thing, is still 16.” As a cultural phenomenon, she said, “Kids have grown up with Harry Potter the way kids in the ‘60s grew up with the Beatles.”

“I think the reason I read the books,” said Spartz, “is not because of the magic or the spells. It’s a great story with wonderful characters. … I’ve experienced a lot of the same things Harry has experienced, the teenage dramas of friends, girls and grades.”

Which is one reason Good, at Scholastic, is taking the long view of things:

“Every year there’s a whole new class of 8-year-olds ready to enter Hogwarts.”