Beijing Confidential by Jan Wong.
Terrific book. In short, it's the true story of a woman (Wong) who was one of the first 2 students permitted to study at Beijing University in 1972. Back then she was a pretty rabid Communist and so when a Chinese student approached her, asking her to help her get to America, Wong and the American student who was with her turned the girl in. She was expelled from the university and disappeared. Wong went back to Canada eventually, became a very successful and acclaimed journalist and so on. This is the story of her return to Beijing, 34 years later, to attempt to find the woman and to see what happened to her and to apologize for what she'd done.
It's really well written - and if you like books written by journalists (it's usually a pretty distinctive style), you will really love it. The descriptions of old Beijing vs. this new incarnation are fascinating. I'd highly recommend it.