The sixth installment of the Harry Potter series is getting high marks from Muggle kids across the region, with many having digested the 652-page tome in a single weekend.

"It was the best beginning of any book I've ever read," raved 10-year-old Nathan Kastner of Rockville, sounding like a mini Roger Ebert. "The beginning was so interesting and unexpected. It really leaves you wondering what's going to happen next."

Some said J.K. Rowling's "Harry Potter and the Half-Blood Prince" had a more serious tone than the other books in the series. Adam Weidman, 14, of Silver Spring said he thought "parts of the book were pretty dark and depressing." He saw parallels between the teenage wizard's fight against the evil Lord Voldemort and the United States's struggle to keep the country safe from terrorism.

"I thought it was a really good read. There was a lot more action" than in the previous installments, said Adam, who stayed up until 5 a.m. Saturday reading the book and finished it at 9 that night.

There were scattered reports that preordered copies of the book weren't delivered as promised. But Muggles (Harry Potter-speak for non-magical people) who received their copies found themselves quickly slipping into reading nirvana.

Kids said they were drawn in by the humor (one of the chapters is titled "An Excess of Phlegm"), the teenage angst (" 'You were going to ask me?' said Ron, in a completely different voice. 'Yes,' said Hermione angrily. 'But obviously if you'd rather I hooked up with McLaggen . . .' ") and the foreshadowing of dark events ("And then, without warning, it swept over him, the dreadful truth, more completely and undeniably than it had until now.")

"I'm on page 453," said Brydie Long, 12, an incoming seventh-grader at St. Bernadette School in Silver Spring. "It's really good. I like how they are teenagers and they're getting in fights and apologizing and stuff. Right now [the story] is kind of quiet, but I think there's going to be more action toward the end."

"Harry Potter and the Half-Blood Prince" continues the adventures of the young wizard and his classmates at Hogwarts School of Witchcraft and Wizardry as they learn to use their powers in the battle against Voldemort.

The first book, "Harry Potter and the Sorcerer's Stone," released in 1998, became a publishing phenomenon. And just as the characters have grown throughout the series -- in the last installment, Harry was a sometimes surly 15-year-old prone to bouts of self-pity -- so too have its readers. Indeed, many of the Washington area fans interviewed yesterday said they continue to see themselves in the characters of Harry, Ron and Hermione, who are now dealing with tougher classes and more complicated relationships.

At Woodley Gardens in Rockville, where five area swim teams gathered yesterday for the annual B Relay Carnival, copies of "Half-Blood Prince" were everywhere. Even a few parents were spied sneaking peeks at the book between events.

Rachel Jung, who preordered her book in April from Borders, had her copy at the pool. The incoming seventh-grader at Montgomery County's Julius West Middle School said she set a goal of finishing all 652 pages in 24 hours.

As of yesterday afternoon, she was close to accomplishing that -- she'd read about 500 pages -- and was raving about the book.

On a scale of one to five?

"A definite 4.9," said Rachel, who originally had to be talked into reading the series by friends. Rachel noted some surprises. The Half-Blood Prince in the title? Not who you think it's going to be, she said.

Elisabeth Huber, 12, of Vienna was so eager to start reading the book that she borrowed it from a family friend until her parents could pick up her preordered copy.

"I've been reading it all day," Elisabeth said. "It's just full of surprises."

Perhaps not as surprising was news from the book's U.S. publisher, Scholastic Inc., that a record 6.9 million copies were sold in the first 24 hours. The previous book in the series, "Harry Potter and the Order of the Phoenix," sold 5 million copies in the first 24 hours of its release in 2003.

Area booksellers said the sales, which began at many bookstores with curfew-busting parties held at midnight Friday, have exceeded their high expectations.

"It's been great," said Morgan McMillian, who manages the children's book department at Politics and Prose in the District. "I can bring out a box of books, and by the time I've got the box open, they're gone."

However, there were reports that Seattle-based, which had guaranteed Saturday delivery for people who ordered from the online retailer by July 11, ran into problems. Some disappointed area families said they did not receive their copies.

The company sent an e-mail yesterday announcing that they were reducing the price of the book by $1 to $16.99 and would be issuing refunds this week for those who had already bought copies. A representative for the company could not be reached for comment.

For Jack Feegel, 12, of Purcellville, the new Harry Potter book will be the first he has read. He was introduced to Harry on the big screen and explained that, this time, he wanted to read the book before the movie came out.

Laura Epstein, 13, who will be an eighth-grader at Eastern Middle School in Silver Spring, is 450 pages through the book. She wasn't offering too many juicy tidbits for those who have not secured their copy.

"All I will say is that there's a huge surprise in the beginning -- it's really amazing what happens. But I don't want to spoil the surprise, so I'm not going to say anymore."

In Harry Potter vs. a Rockville swim meet, it was no contest for Stephen Babendreier, 12, who chose to pore through the 652-page "Harry Potter and the Half-Blood Prince."