Rivalry is an attempt to understand facets of entrepreneurial societies by integrating the economic analysis with historical, political and psychological considerations, customarily shunned by economists. The author argues that decisions to make new business ventures, and readiness to take risks are both related to concepts of ranking hierarchies on local, national or international levels. He then constructs a theory of business enterprise and of rivalry supported by evidence on entrepreneurship, innovation, advertising, all examined with their historical, political or organisational concerns. This notion of rivalry among businessmen is used to derive guidelines for anti-trust legislation. Instead of pricing, profitability, concentration ratios and other criteria used today to infer non-competitive behaviour, he suggests using a measure of a firm's relative rate of innovation to infer it. By extending the notion of rivalry to the political sphere, national and international, guidelines are derived to evaluate the performance of state-owned enterprises and to examine policies related to free trade.