Entrepreneurs, as most people know, are risk-takers who thrive on uncertainty and change, always on the lookout for their next startup. But according to new research from Wharton management professor Ian C. MacMillan and co-author Vipin Gupta, entrepreneurs aren't the only ones who should be able to operate in unpredictable, high-risk environments. Drawing on an extensive worldwide survey of middle managers, the two authors outline the qualities that define "entrepreneurial leaders."