Today would have been Murray Rothbard’s 93nd birthday. He was an unforgettable friend, whose immense knowledge of many different fields was unsurpassed in my experience. In a lecture on the Austrian Theory of the Business Cycle, he mentioned the common objection that the expansion of bank credit might have no effect, if investors anticipated trouble. After the lecture, I asked whether Mises had answered this point. He said, “See his response to Lachmann in Economica, 1943.” I often went to used bookstores with him, in both Palo Alto and Manhattan, and listened to him as he commented on nearly every book on the shelves. When he was a student at Columbia, he admired the philosopher Ernest Nagel, who he said would always encourage students to do new work. Murray was like this himself. He constantly encouraged students to work on Austrian and libertarian topics. His support for me was never failing, and I owe him everything. If only he were still here now, to guide and instruct us!