ITHACA, N.Y. -- Ten minutes into the blockbuster movie "Spider-Man 2," nerdy physics student Peter Parker (played by Tobey Maguire) -- whose alter ego is the superhero Spider-Man -- trips and spills his armful of books while racing to class at Columbia University. As he bends to pick them up amid an onslaught of passing book bags, the camera zooms in on the maroon cover of the book atop the stack: Introductory Quantum Mechanics , fourth edition by Richard L. Liboff of Cornell University. Then the book gets stepped on.

Liboff, an emeritus professor in the School of Electrical and Computer Engineering who still works on physics problems in his Cornell office every day, was delighted when one of his students told him that his book is featured in the science fiction-action thriller. "It's a great advertisement … and now I have people calling me up," he said. The same student tried to "sponge" answers to two homework problems while telling him about the movie, Liboff recalls with a smile.

"A full-time retired professor," Liboff admits that he hasn't actually seen the complete movie. An Ithaca theater gave him and his wife free tickets, but the physicist left after the dropped-book scene. "It lasts for about one microsecond," Liboff says. However, the scene is a key one in the movie, establishing Parker's scientific talents, his teenage insecurity and his difficulty in balancing his life as a student and a superhero.

Blakeley Kim, who designed the book's cover along with Kenneth Probst for San Francisco publisher Addison-Wesley, says that had he known 50 million people would catch a glimpse of his work, he might have made it a bit bolder. "We wanted it to stand out among all the books on a physics professor's bookshelf.… It was a real challenge to try to represent quantum mechanics in a visually appealing way, and I think we did well."

Adam Black, Liboff's editor at Addison-Wesley and the person who first spotted the book in the film, sent 120 of the publisher's employees an e-mail boasting of "the only physics book fit for superheroes" and "where Spider-Man learns his death-defying physics from." Says Kim, "It was a company pride sort of thing."

No one, including officials at Sony Pictures and Columbia University, seems quite sure how Liboff's text ended up in "Spider-Man 2." Liboff conjectures that someone from the film crew walked up to Columbia's physics department during the shooting and asked for some appropriate books. "It's used at all the good schools, and all the bad schools, and just about everywhere," he says.

Introductory Quantum Mechanics was first published by Holden-Day in 1980. Since its first printing with Addison-Wesley in 1987, it has sold an estimated 100,000 copies -- a number that is off the charts as college textbooks go. "It is probably the best-selling quantum mechanics textbook in the world at its level," says Black.

The book is in good company. "Spider-Man 2" grossed $40.4 million on, Wednesday, June 30, the biggest opening day for any film in history. After six weeks in the box office, the film grossed $354.4 million, making it No. 10 on the list of all-time top grossing films in the United States. Even so, Black doubts that the movie will boost book sales. "If you figure 5,000 physics students graduate each year, and we sell about 5,000 copies of Liboff's book each year, then everyone already has it," he says.

Liboff, a Brooklyn, N.Y., native who joined the Cornell faculty in 1964, developed the idea for the book while he was a graduate student at New York University. "Quantum mechanics is the science of very small particles and systems, where classical physics breaks down and you have to use the Schrödinger equation," he says. "Most people don't know who Schrödinger is, but what he did relates to everything you do: automobiles, TV, surgery, radios … everywhere. That's quantum mechanics."

Introductory Quantum Mechanics, fourth edition (Addison-Wesley, 2003), can be purchased at your local college bookstore or online at http://www.aw.com. It costs $97.

This story was reported and written by Cornell News Service intern Thomas Oberst.