A proper conception of man's nature is indispensable to the science of economics, which studies man in his capacity as a producer and exchanger of material values. In the history of economic thought, the concept of "economic man" is purportedly the concept of man as both rational and selfish in his economic activities. Economic laws have been seated on his shoulders. But erroneous theories of rationality and selfishness have ·irlurdered economic man, thereby undermining the laws of economics . These lectures will show how only the Objectivist conception of man's nature can rebuild economic man and the laws of economics.