By Owen Gleiberman
Updated July 27, 2012 at 04:00 AM EDT
Ted Alcorn

The Chinese artist and activist Ai Weiwei has achieved a prominence that makes him, in effect, the Aleksandr Solzhenitsyn of the Twitter age. He’s also the least stuffy of dissidents, and Alison Klayman’s stirring, important documentary catches his complex humanity. For years Ai has been allowed to express himself — in conceptual art, Internet docs, and merrily moralistic tweets — due to the political reform in China (though he’s aware he could be jailed at any time, and has been). Yet he insists on illuminating the darkest corners of what is still a dictatorship. Klayman spent months with Ai in his Beijing home studio, and also in London and Munich, where he stages art shows of stunning vastness. He radiates a mischievous sense of the absurdity — and necessity — of one man tossing stones at a regime this gigantic. A