Research on international relations at Northwestern University in the 1960s and 1970s revolved around Harold Guetzkow's pioneering work on the simulation of international processes. As a beginning faculty member, I benefited from the insights and excitement of that special time and place. As a participant in one of his events, I experienced the challenges he faced in carrying off the complex operation of man-machine simulation, when the machines consisted of typewriters, thermofax machines, and a mainframe computers with punch-card input. As a beneficiary of the revolution introduced by networked microcomputers, I realized that Guetzkow's successes would have been multiplied many times over if the proper technology had been available to him.