I have just returned from the professor's 70th birthday party and a conference to honor his academic achievements.
A lot of people have offered their views of the Professor's contribution to economics. In my opinion, professor Qian Yingyi of UC Berkeley probably has delivered the best presentation on the topic.
If my memory serves me right, his message is this:
Professor Qian considers "The Theory of Price Control" (1974 Journal of Law and Economics) to be the most important paper the Professor has ever written. In the traditional discussion of price control, people tend to subsume the discussion under a larger debate on whether the state or the market is a better mechanism for resources allocation.
The Professor goes beyond that according to Qian. The professor first asks the question, what will happen if price control is introduced. His answer is rent-dissipation. But the professor does not stop there. He then asks what people will do to minimize rent-dissipation. Because people will act to minimize rent-dissipation, the Professor then concludes that whatever rent is dissipated has to be a constrained minimum.