Why do some new ventures succeed while others fail? What is the essence of entrepreneurship? Who is most likely to become a successful entrepreneur and why? How do entrepreneurs make decisions? What market, regulatory, and organizational environments foster the most successful entrepreneurial activities? Entrepreneurship research is plagued by these and other fundamental unanswered questions, for which there does not exist a cohesive explanatory, predictive, or normative theory. In this article we identify major challenges for entrepreneurship theory development, and offer insights into promising directions for future research. Our conclusion suggests that it may be too ambitious to expect a complete and robust theory due to the interdisciplinary nature of entrepreneurship. However, we show that by integrating perspectives and by applying analytic, empirical and experimental tools from a range of fields, some of the fundamental questions can be answered.