Outspoken, provocative, and prolific, the artist Ai Weiwei is an international phenomenon. In recent years, he has produced an astonishingly varied body of work while continuing his role as activist, provocateur, and conscience of a nation. Ai Weiwei is under "city arrest" in Beijing after an 81-day imprisonment; he is accused of tax evasion, but many suspect he is being punished for his political activism, including his exposure of shoddy school building practices that led to the deaths of thousands of children in the 2008 Sichuan earthquake. In 2009, he was badly beaten by the police...