It took just two days for Molly Bagley to become addicted to the hottest series in young adult literature since Harry Potter.

Previously a librarian at a junior high school, Bagley, now the young adult coordinator at Reddick Public Library, watched a steady stream of students come into the library asking for "Eclipse," the third book in the "Twilight" series.

Deciding she should find out what was creating the buzz, Bagley, 26, brought home the first 500-page book, "Twilight," during Christmas vacation.

"I read it in two days," she said, then laughed and confessed. "Then I went back to the library (during the break) and got the other two books. They are very addictive."

Now the series is coming to an end -- sort of. The fourth and final installment of the series, "Breaking Dawn," will be released at 12:01 a.m. Saturday, Aug. 2. However, author Stephenie Meyer has promised at least one other book, "Midnight Sun," will be released to tell "Twilight" from another character's point of view.

The books revolve around the love story of Edward, a vampire, and Bella, a human. Jacob, Bella's werewolf friend, also is in love with Bella.

"Everyone is in love with Edward," Bagley said about the love triangle. "But I'm pulling for Jacob."

While the story line may seem bizarre, the tale has struck a chord with teens who have devoured 5.5 million copies of the books worldwide. Each book hit the New York Times bestseller list, with the second, "New Moon," and the third, "Eclipse," heading straight to the No. 1 slot upon release.

"We can't keep the books on the shelves," said Bagley.

Patti Smith, assistant director at Robert W. Rowe Public Library in Sheridan, said interest in the books usually begins around age 12 and continues into high school.

"The 'Twilight' series is popular with both kids and adults alike, especially the girls," she said. "We can't keep these books on the shelves. They go out as fast as they come in. But we even have had many adults that have checked these out, too. Again all women."

Eileen Fesco, owner of the Book Mouse in downtown Ottawa, said all three books have been big sellers in her store, though it took time for readers to fall in love with the series.

In 2005, the year "Twilight" was released, she sold one hard copy of the book. By the time the paperback edition was released, the book had become a hit and she sold 83 copies.

"Anything over six (books sold) is a hot seller here," she said. "So 83 -- that's huge."

Sales of the "New Moon" and "Eclipse" sold 67 and 48 copies, respectively. But the drop in numbers does not indicate waning interest. As a series becomes popular, chains that normally don't sell large numbers of books, such as Kroger and Wal-Mart, also begin stocking the books. That pulls from the sales of independent book stores, she said.

Fesco predicts "Breaking Dawn" will continue the bestselling trend.

"It will be the biggest book this year," she said. "Unless there is a huge blockbuster before Christmas."

Gabby Lundy, 12, of Ottawa is eagerly awaiting the book's final chapter, having become hooked on the series when her friend recommended it. Now she and all her friends spend time talking about the story.

"It's a good story that kept me reading," she said. "I got excited with Bella as she found out about Edward being a vampire."

"I like the way each book is different," she added. "They're not all the same. They still have the same characters, though, and the same personalities."

Meyer's success with the series has been likened to the craze surrounding the Harry Potter books, but Fesco wouldn't go that far.

"Harry Potter is a whole ball game in and of itself," she said. "But kids are addicted (to the "Twilight" series), and I hear that they are talking to their teachers about it. They'll say to their moms or their teachers, 'You have to read this.' And they like them, too. That's amazing for a teen novel."

The appeal of the books comes mostly from its romantic story of two star-crossed lovers, which is not sexually charged, as are many modern vampire tales.

"They may kiss or hold hands, but it's all very innocent," said Bagley. "There is some violence with the battles, but it's not gory. What adds to the appeal is the attention to the romantic tension."

"I think the girls like these books because it combines romance with the mythological and dark countenance aspect of werewolves and vampires," agreed Smith.

Fesco said books for younger readers have been generating more and more business for book sellers, as evidenced by the number of libraries and bookstores -- including hers -- that host book release parties to celebrate these volumes. And it's not uncommon for the young people who buy these books to immediately begin reading the story, even if they purchased it just after a midnight release.

Michaela Murphy is one of those avid readers. When the 12-year-old rural Sheridan resident learned her family's vacation would coincide with the release date of "Breaking Dawn," she e-mailed a bookstore about 90 minutes from where they will be staying in Minnesota to make sure she would receive a copy Aug. 2 rather than waiting until her family came home Aug. 3.

After reading the first chapter of "Breaking Dawn" released earlier by the publisher, she was even more eager to find out how the series will end.

"I'm really happy (my parents) were willing," she said, noting her mother took her older sister to a midnight book release party for one of the Harry Potter books. "I really want to know what happens."

Michaela was introduced to the series by a friend at school and quickly got caught up in the story line.

"I like that it's a love story and how they are kept apart because of their differences. And then, there's action to balance that out," she said.

"I like happy endings and I'd like this ending to be happily ever after," she added, saying that she's rooting for Edward.

"Jacob is like a brother. I like him, but I like Edward better."