I just attended a two day conference at UCLA where leading economists discussed Harold Demsetz's core contributions. As you can see from his Google Scholar citations, there is a lot to talk about. Harold and Rita Demsetz attended the conference and Harold had a lot to say! I heard some very interesting talks by Oliver Hart, Oliver Williamson, Sam Peltzman, Bob Topel, Dennis Carlton and Boyan Jovanovic. Several of his past students attended the conference and supplied amusing stories about him as a teacher and mentor. To my surprise, I can't find a conference program to link to but that's how UCLA does things.
Harold is a role model for me and many other members of the UCLA faculty. Not all 82 year old economists are so active and clear thinking. In the Chicago tradition, he asks tough, clear questions. I always try to have lunch with him and he is always willing to hear me out and debate any of my crazy ideas.