"Zathura" is easy to spot among children's picture books. Very few are in black and white. And even fewer have a gold sticker proclaiming "Now a Major Motion Picture!"

Author-illustrator Chris Van Allsburg laughs loudly into the phone when this is pointed out. "They assume that people will go into bookstores and not recognize it right away," he says.

The 2002 book is very different from Van Allsburg's rich and colorful "The Polar Express" and the photo-like images of "Jumanji." So it might take some imagination to see how this 32-page book of charcoal-black pencil drawings on a textured background could become a sometimes-scary, special-effects space adventure.

Van Allsburg, of course, is not surprised. Moviemakers had for a long time been asking for a sequel to "Jumanji," which became a successful 1995 film starring Robin Williams. In the story, a jungle-adventure board game comes to life, and the players have to deal with a lion, destructive monkeys and an erupting volcano.

But what happened after the book ends, Van Allsburg was often asked, when brothers Danny and Walter are seen walking off with the Jumanji game?

Van Allsburg loves to make readers wonder about the outcome of a story. When he creates a book, he forms a picture in his mind and then wonders what might happen next. (The words are the hardest part for him, he says.) Over the course of about seven months, he creates detailed drawings, keeping his work private until he has finished. "I usually don't show people what I'm doing," he says. "If they don't like it, what am I supposed to do with that information?"

So, what happens next?

In the book "Zathura," Danny is quickly bored by the jungle game but finds a space-themed game in the same box. When he begins to play the game, his house is transported into space, where Danny and Walter encounter a meteor shower, a crazed robot and a Zorgon alien.

The nearly two-hour "Zathura" movie, which is rated PG and opens in theaters tomorrow, is much more complex than the book: Characters have been added; Danny's relationship with his brother is more complicated; the game is more elaborate; and there's no mention of Jumanji.

The changes don't seem to bother Van Allsburg. (He enjoyed the movie, which he said is more inspired by the book than based on it.) "You can't expect for it to be a cinematic duplication of what exists on the page," he says. "That wouldn't make a good movie anyway."

-- Scott Moore

Game on: From left, Jonah Bobo, Kristen Stewart, Dax Shepard and Josh Hutcherson in "Zathura."