The human rights record within China seems to rise and fall over time, but it's very clear that in the run up to the 2008 Beijing Olympics and since then, there's been a greater intolerance of dissent and the human rights record of China has been going in the wrong direction.
On top of my to-do list in preparing for Beijing is 'On China' by Henry Kissinger, who has had firsthand experience with every top Chinese leader since Mao, so his insights are valuable and his access is perhaps unrivaled.