'When Steve Jobs died, I was mystified," says Oscar-winning documentarian Alex Gibney at the start of Steve Jobs: The Man in the Machine, over a montage of news clips and, yes, iPhone videos of mourners lining up to pay homage at Apple stores around the world.

As tearful throngs lay flowers beneath portraits of the Apple cofounder - he died Oct. 5, 2011, at age 56 after a long battle with cancer - Gibney puzzles over how someone who wasn't a pop singer or a civil-rights leader could inspire such an outpouring of emotion, devotion, grief.

Here was this Silicon Valley whiz kid who began his career hacking Ma Bell (he sold Blue Boxes, an illegal device that let people make free phone calls anywhere in the world); who marketed the personal computer with the fervor of a Bible salesman; who quoted Bob Dylan; who, through the ups and downs of his career, treated a number of colleagues and intimates in decidedly unheroic ways. He was a savvy entrepreneur with a keen design aesthetic.

"He created technology that people love," says Al Gore. And that's true enough.

For just over two hours, Gibney probes and parses the Jobs biography, the revolutionary debuts of the iPod, the iPhone, the iPad, the transformation of iTunes into a music and video giant, of Pixar into the leader of the animated-film industry. It's an American success story, to be sure. A kid given up for adoption becomes one of the richest, most powerful corporate chieftains on Earth, shifting the paradigms while he's at it.

There is - or was - a dark side, of course. Much of Gibney's provocative film is devoted to getting at the deeply conflicted nature of its subject: a dreamer drawn to Eastern spiritualism, who could lie, cheat, and bully, let his family and friends down, let his business thrive while his company exploited cheap labor markets in China, dodge taxes via Ireland.

Readers of Walter Isaacson's Steve Jobs book already know a lot of what Gibney covers. But the mix of talking-head interviews, archival footage, and long takes from a 2008 SEC deposition (Jobs is blunt and blase, irritable and squirmy, forced to answer questions about illegal backdated stock options) brings home the complexities and contradictions of the man.

It doesn't come as any kind of revelation, but central to Gibney's film is the idea that the products Jobs shepherded into the world - designed to bring people closer, to facilitate and foster communication - have, in many ways, made them more insular and isolated. "The alone together phenomenon."

That, too, is part of Jobs' legacy, Gibney says. We're glued to the brilliant little gizmos cradled in our hands, the tablets we grab whenever there's a chance.

It's like "Frodo's ring," says Gibney, who admits that even he still keeps his iPhone close by.