Harry Potter can still work his magic at the cash register.

Hours after the announcement Tuesday that the sixth installment in the boy-wizard series will appear on bookshelves on July 16, "Harry Potter and the Half-Blood Prince" shot to the top of the best-seller lists due to a rush of pre-sales.

Stocks of publishers and book retailers rose sharply, too.

In a literary development sure to spark a "Who shot J.R.?" debate among the series' young fans--and to create sales buzz--author J.K. Rowling teased that one of the main characters will be killed in the sixth book. She has also said the seventh book will be the last in the series.

Pre-sale orders landed "Half-Blood Prince" in the No. 1 spot on Barnes & Noble's Top 100 and on Amazon.com's best-seller list as of Tuesday evening. Both are selling the book for $18, 40 percent lower than the $30 suggested price.

Shares of Scholastic Corp., the book's U.S. publisher, rose 4.2 percent Tuesday to close at $37.44 and surpass its 52-week high. In London, Rowling's British publisher Bloomsbury Publishing PLC saw shares surge 7 percent to an all-time high of $5.69.

Retailers saw share gains, too. Borders Group Inc. added 1.5 percent, Barnes & Noble Inc. rose 2.5 percent and Amazon.com Inc. gained 1.1 percent.

"The release of Harry Potter No. 6 is expected to be a major publishing event in 2005, with the book likely to be, by a large margin, the largest-selling trade book of the year," Goldman Sachs analyst Peter Appert said in a note about Scholastic.

The sixth book could sell about 11.6 million copies nationally, "which appears realistic when compared to the 13.4 million hard-cover copies of Harry Potter No. 5 currently in U.S. circulation," he said.

Indeed, expectations among booksellers will be high.

"Sales from the last Harry Potter book grossed as much as a major Hollywood movie in its first week of release," Steve Riggio, chief executive officer of Barnes & Noble, said in a statement Tuesday.

"We expect this next book in the series to make publishing history once again. We've already collected 500,000 e-mail requests from our customers waiting to be notified of the date of the next book. so this announcement is very welcome news for readers everywhere."

About 260 million copies of the fantasy series, which debuted in 1997, have sold worldwide.

Barbara's Bookstore, a Chicago chain, said it will order a similar number of initial copies for the sixth Harry Potter as it did the fifth.

"Expectations are that it will be as big as the previous ones," General Manager Debi Morris said. Moreover, the question of which character gets killed off "certainly keeps people interested in reading it," she said.

If the past is the best indicator of future success, Rowling likely has another hit.

"Harry Potter and the Order of the Phoenix," the series' fifth book, was released on June 21, 2003, and became the fastest-selling title in history on the first weekend of its publication. All five Harry Potter books have been No. 1 best-sellers.

"It looks like Christmas will be coming in July next year," Allan MacDougall, chief executive officer of Raincoast Books, Potter's Canadian publisher, said in a statement. Raincoast has sold 8 million copies of the first five books in the series, making it the best-selling series in Canadian publishing history.

The sixth takes up the story of the adolescent's sixth year at Hogwarts School of Witchcraft and Wizardry.

As recently as Dec. 10, Rowling, who is pregnant with her third child, sounded like the sixth book wouldn't arrive soon.

"I have nothing noteworthy to report because I have been spending nearly all my time sitting in front of my computer writing, re-writing and taking the occasional break to bang my head off the desk in frustration or rub my hands together in fiendish glee," she said on her Web site, jkrowling.com.

The Associated Press contributed to this report.