With the broad, essentially American theme that man is self-made, director Jon Favreau's Iron Man is made of solid, durable stuff. Light, humorous, and entertaining, Robert Downey, Jr. gets the Marvel Studios comic book adaptation up and running and he doesn't let up in the year's best action movie so far.

Downey plays Tony Stark, an industrialist in the military weapons business and a playboy after dark. He's like an exceptionally bright hedonist with a heart of gold, downing booze and seducing babes while creating superior missile technology, usually in the same day, but he's not a pig about it. Downey, delivering lines with aplomb, does Stark with a wink, making an otherwise implausible character come alive.

One day, as he heads back to base after a test firing in Afghanistan, he's captured by the enemy, held prisoner and paired with another captive. The presumably Moslem terrorists, led by a bald baddie, don't want to behead the U.S. top gun; they want to use what comes from inside Tony's head. Tony Stark, unlike other bland superhero alter egos, has a mind of his own. His response? "I refuse."

In other words, he's downright American and proud of it. During captivity, Tony's spirit of independence propels his creation of an armored suit fitted with blowtorches and flight capability. Iron Man moves the story from faraway lands, and it works, though it would have been much more rewarding to see patriotic Iron Man scorch those that sponsored the attack on New York and Washington.

Returning to southern California after the ordeal with new insights and new body parts, he reconfigures the business and, though the premise of his change of heart is too vague, Tony's redesign rocks those around him.

Among those concerned are his Air Force best friend (spot on Terrence Howard with the movie's biggest laugh line), his uncommonly competent secretary (Gwyneth Paltrow) and the company's top executive (Jeff Bridges), a bald, bearded bean counter with a taste for pizza. None of them gets behind the idea of a weapons manufacturer that no longer makes weapons.

Tony's goals and motivation are a mix. He neither comes out and states his intentions nor what seems to be his main reason for ditching that product line: that he seeks to produce better U.S. weapons so our armed forces are protected and prepared. The nebulous nature of his business plan, and its corollary plot twist, saps Iron Man's energy. Without a formidable adversary, the picture tends to sag.

Tony and Iron Man are best suited to his stunning, super-modern Malibu home, with vintage automobiles, ocean views and highly developed robotic tools. It's here that Tony—reinvigorated to create better machines after seeing young Americans being killed—rebuilds himself as Iron Man. He throws in a few cracks to the robots along the way.

Downey's humor is rich and delightful—he's always good and it's great to have him back on screen—and the sarcasm doesn't come at the expense of the story. The high-powered businessman must learn to accept his limitations, to repeat experiments and again and to realize that perfection doesn't mean infallibility. When Tony hits ignition, he's earned it.

His inner Iron Man puts himself first, whether ordering a cheeseburger, running the business which bears his name or, in his first solo flight, shooting for the moon. Tony's self-created hero is flawed, certainly, and he has a way to go before defending America, making a profit on the new venture and getting the girl, but the focus is not on his flaws and this hero has the brains to match the heart. For a good, swift start to summer fun, Iron Man is a blast.