ON MAY 28, 2009, the readers of artist and activist Ai Weiwei's blog — hosted on Sina, a popular Chinese internet portal — logged onto blog.sina.com.cn/aiweiwei to find the message "This blog has already been closed. If you have queries, please dial 95105670." That message is still there, although the number has changed. Dialing it takes you to an unfolding origami of recorded options that would frustrate the most hardy call center veteran. When human contact is finally made, an explanation as to why the blog was shut down is not forthcoming. Nor, for those who've been following Ai's career, is it necessary.

Ai the artist wooed controversy long before he became known as a political activist. Son of the poet Ai Qing — a prominent literary figure in the Chinese Communist Party (CCP) before he was denounced as a rightist in 1957 — Ai Weiwei has been on the fringes of free speech and democracy activism since the late seventies. In Beijing, he made a name for himself as a counterculture artist and architect, co-curating one exhibition with the English title "Fuck Off." In October 2005, as one of Sina's first celebrity bloggers, he found a new means by which to rock the boat.

In the months before his blog was censored, Ai used it to popularize a "citizen investigation" that aimed to document the names of the thousands of students who died in the 2008 earthquake in Sichuan, many as a result of "tofu dregs" construction that saw schools collapse while cadres pocketed the surplus from skimped building costs. Given the blog's loudmouthed criticism of Chinese authorities across a range of other issues, and the routine censorship of other internet sites, it was no surprise that Ai's platform got the axe.

"Ever since the Sina blog was closed," Ai has since remarked, "I've had a feeling of weightlessness." He moved his virtual home to U.S. servers at blog.aiweiwei.com, and threw himself into a new form of expression on Twitter ("In the Chinese language, 140 characters is a novella"). Online and off, he was as sharp a stone in the Party's shoe as ever, and continued his investigation in Sichuan despite run-ins with the police and a serious head injury he sustained during one such clash.

Last April, in an ugly twist, Ai was arrested. Vague charges of tax evasion fooled no one in the midst of the ongoing crackdown, with Ai falling almost completely out of contact for over two months. He was released on bail in mid-June and, despite the occasional return to rambunctious form on Twitter (@aiww), he has been tellingly quiet in the months since. A close associate of his told Reuters that Ai was threatened with ten years' imprisonment for inciting state subversion, and that his blog and Twitter feed were discussed "line by line" while he was in police custody.

Ai Weiwei's Blog is a selection of his posts in translation spanning 2006 to 2009, published the same month that Ai was arrested, and thrown into a fresh light by the drama that has ensued. An archive of one of China's most lively dissenting broadcasts, it tells a story that continues beyond its last page, the ending to which is still anyone's guess (one hopes for a "Volume Two").

The publication is also among the first of a relatively new breed: the book of the blog. Challenger to the essay collection and substitute for volume of correspondence (Collected Emailsdoesn't have the same ring), this is an exciting form...