Nonetheless, various theoretical traditions in the field have adopted radically different interpretations with respect to these assumptions of entrepreneurial phenomena, therefore arriving at different explanations of these phenomena. "Theories of Entrepreneurship" investigates two sets of assumptions about the nature of opportunities, the nature of entrepreneurs, and the nature of the decision making context within which entrepreneurs operate. It is suggested that these two sets of assumptions constitute logically consistent theories of entrepreneurship. Moreover, these two theories are complementary and can be applied to widely studied entrepreneurial phenomena - the organization of the entrepreneurial firm. These applications demonstrate both the differences between these two theories and how they can be complementary in nature. "Theories of Entrepreneurship" sets the basis for future explorations into entrepreneurship theory. Students and researchers alike will benefit from the framework presented by the author in developing the theoretical underpinnings of entrepreneurship.