The entertainment world witnessed a very unusual event last weekend: a book outgrossed Hollywood’s biggest blockbuster.

Scholastic sold an estimated 5 million copies of “Harry Potter and the Order of the Phoenix” in its first 24 hours on sale, generating close to $100 million in sales revenue. Universal Pictures’ box office-topping, CGI-driven tentpole “The Hulk,” by contrast, took three days to amass $62 million in ticket sales.

The robust book sales are good news for Scholastic, but the question facing other publishers is, will Harry lift all boats, restoring a slumping book trade to a healthy level of profitability? And is the type of “event” publishing that Harry typifies good for the business?

Most agree that if the book biz is on the upswing, Harry can’t take all the credit.

A few days before “Order of the Phoenix” arrived, booksellers got a big boost from “Living History,” Hillary Clinton’s memoir from Simon & Schuster, which posted record sales of nearly 600,000 copies in its first week of release.

S&S CEO Jack Romanos called it “the fastest selling nonfiction book in the history of our industry.”

Talkshow maven Oprah Winfrey also is doing her part for publishers. Winfrey announced last week that she’s reviving her book club, which for six years served as a powerful sales mechanism for fiction by unknown writers.

There’s one wrinkle. Winfrey’s book club will showcase classics, not new books. Her first pick: John Steinbeck’s “East of Eden.” At press time, the Penguin edition of Steinbeck’s novel had climbed to the third slot on Amazon’s bestseller list.

BLOCKBUSTER BOOKS like Harry and Hillary carry some of the same risks as blockbuster movies.

They call for huge advances and marketing expenditures. They overshadow smaller titles, which tend to see their resources siphoned away to feed the mega-hits.

And to a degree, their value as books is eclipsed by the media and licensing blitz that surrounds them.

To be sure, “Phoenix” will bring long hours of reading pleasure to millions of readers. But it’s also a cog in a corporate machine that involves big merchandising campaigns and significant media tie-ins.

This is the first Potter book to appear since the films were released, and the increased sales arguably reflect a larger audience that’s seen the movies, played the Harry PlayStation game, eaten Harry candy, enjoyed the Harry action figures and Legos and slept on Harry sheets while wearing Harry pajamas.

AMERICAN BOOKSELLERS ASSN. CEO Avin Mark Domnitz said the vigorous sales of Hilary and Harry will have “an overwhelmingly positive influence” on the book trade.

“It focuses a wide range of people on books,” Domnitz said. “To the extent people go into bookstores, just to take part in the fun, the focus of activity is on books, and that’s great for all segments of the business.”

Smart booksellers, he added, “will figure out how to leverage this mass hysteria to other books” — and not just books that appeal to Harry’s readers. Hot novels like “The Da Vinci Code” and “The Devil Wears Prada” also stand to benefit from the increased bookstore traffic.

But Harry is in a class by himself. The last time the release of a book generated more sales receipts than the movies in the marketplace was the July 7-9, 2000, weekend. It was “Harry Potter and the Goblet of Fire,” and it sold 3 million copies in its first weekend on sale. The top pic that weekend was “Scary Movie,” which bowed to $42.5 million.

On Tuesday, Scholastic announced it had gone back to press for additional 800,000 copies of “Phoenix,” bringing the total print run to 9.3 million copies.

At that rate, even Drew Barrymore, Cameron Diaz and Lucy Liu, whose “Charlie’s Angels: Full Throttle” hits theaters Friday, had better make way.