This actually isn't the first time the Autobots and Decepticons have invaded multiplexes. In 1986, the animated Transformers: The Movie was released in theaters, bringing together the weirdly eclectic vocal talents of Judd Nelson, Leonard Nimoy, Eric Idle, Robert Stack, and, in his final film role, Orson Welles as Unicron. During the film's production, the man who'd brought the world Citizen Kane had been ailing. Shortly before he died, Welles told a biographer he'd spent the day ''playing a toy.'' To the legions of kids who'd spent countless hours splayed on their bedroom shag carpets with them, though, those toys were as treasured as Kane's own Rosebud — if Rosebud could shoot heat-seeking missiles from his arms.

Initially created by a Japanese company called Takara, the toys had been introduced in the U.S. by Hasbro in 1984 and quickly expanded into TV cartoons and Marvel comic books. The Transformers captured the prepubescent imagination. Soon, what had begun as just a nifty plaything had developed into an entire universe with its own complex mythology, much of it focused on the Transformers' home planet of Cybertron, populated by everything from Dinobots to Micromasters to Aerialbots to Combaticons.

Still, the 1986 movie proved a giant flopicon at the box office and incurred the wrath of fanboys for killing off the John Wayne of Transformers, Optimus Prime. Hollywood lost its enthusiasm. Who needed giant robots when you had Schwarzenegger and Stallone? For years, while new Transformers toys and cartoons kept the brand alive, the prospects for a movie seemed dim. In 2003, when producers Tom DeSanto and Don Murphy started pitching the idea of a new Transformers movie around Hollywood, studio executives were largely uninterested. ''We were met with befuddlement,'' says DeSanto. '''This is a truck that turns into a robot and he's going to battle the airplane that turns into a robot? And they're how tall?' It just wasn't their generation.''

There was one executive who got it, however — and he happened to be the most powerful kid in town. Spielberg grabbed on to the idea of a Transformers film and ran. DreamWorks and Paramount came on board, instantly transforming the project from a quaintly nostalgic nonstarter into a would-be blockbuster. ''Steven was the architect of this from day one,'' says DreamWorks production head Adam Goodman. ''He had played with the toys both with his kids and, quite frankly, by himself. He had a passion for it.'' Spielberg lured screenwriters Roberto Orci and Alex Kurtzman (Mission: Impossible III) with a simple, human-interest pitch straight out of the E.T. playbook. ''He said, 'It's about a boy and his car,''' says Orci. ''That's all we needed to know.'' When Bay got Spielberg's call, he was initially reluctant, but a trip to Hasbro changed his mind. ''We went through the entire lore of Transformers. I'm like, God, you know, if I make it real and edgy it might be something really interesting.''

With Bay on board, Spielberg supported casting LaBeouf, 21, as the teen Everyman who gets ensnared in the robot war. The boyish actor, then slowly gaining traction with audiences through films like Holes and I, Robot, was being groomed by Spielberg to be a young Tom Hanks — hardly the chiseled hero typically associated with Bay's movies. ''The girls in the office, they always rate the actors coming in here,'' says Bay. ''They were like, 'Nope, he's not hot.' I said, 'Just watch the [audition] tape.' And they saw it and they're like, 'Oh, my God, we love him.''' (Spielberg was unavailable for an interview; he's at work on LaBeouf's next project, Indy 4.)

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