I arrived in Hangzhou on a plane from Beijing one Saturday in August. Wen picked me up at the airport. We had met once, years before, at an international gathering in Jakarta. Back then, at dinner one night, the Americans around the table had argued over China policy. Afterward, I'd given Wen my card, telling him, a bit apprehensively, that I was pretty tough on his government. "Please continue," he'd said. I had often remembered that encounter but never expected to see him again. It was a surprise to find he would be my guide for the second leg of a trip friends had helped arrange so that I could meet Chinese dissidents in Beijing and Hangzhou.

The week before I arrived, some 40 intellectuals, journalists, lawyers, and human rights activists had released a letter decrying the condition of human rights, particularly at a time when Chinese leaders were using the 2008 Summer Olympic Games, to be held in Beijing, to enhance China's international prestige. Over the ten days I was in China, I met several dissidents who had signed the open letter.

Hangzhou is a tourist city with a large lake and historic villas where Mao Zedong, Chiang Kai-shek, and literary figures used to vacation. Wen, who is in his mid-30s, spent several years working in the import-export business before turning more or less full time to writing and civic action. Fifteen minutes into our ride, he told me that two black cars had been with us since the airport. They followed us for the next three days.

I hadn't noticed any surveillance in Beijing, and neither had my guide there--a scientist whose career had been derailed by his involvement in the protests at Tiananmen Square, violently suppressed by the government on June 4, 1989. Yet I'd visited one of China's most prominent dissidents, Ding Zilin, the mother of a teenager killed in the Tiananmen massacre. Possibly someone watching her apartment, or that of another dissident I visited, the literary critic Liu Xiaobo, had seen me and alerted the authorities in Hangzhou. Before my trip, my friends and I had agreed that it was actually a good thing for the authorities to know the dissidents had supporters outside China. Now, seeing the black cars in the side-view mirror, I still believed that, but I couldn't help worrying.

Wen had planned to register my hotel room in his name so I wouldn't have to turn over my passport to the hotel, which reports information to security officials. We went through with this plan even though it didn't make sense any more. Over the next few days I met with a human rights lawyer, a journalist who had been fired for reporting on the demolition of an unauthorized church building, and a writer who publishes articles with titles like "Hu Jintao: Kneel Down Before Me" on overseas Chinese websites.

The dissidents in China walk a tightrope. The Communist party allows certain things, but draws the line at others. The dissidents I am writing about here communicate fairly easily with each other and with the outside world. When they are careful, there is a kind of modus vivendi with the authorities. But there are some things they know they cannot do without serious consequences.