Entrepreneurs' behavior is a key construct in understanding how entrepreneurs create new organizations. We define entrepreneurs' behavior as concrete and observable, and distinguish it from related concepts. In reviewing the literature in top entrepreneurship and management journals, we note that behaviors are poorly defined and the cumulative research is fragmented with often ad hoc measures lacking important validation in many studies. To better define behavior, we outline taxonomic (types of behavior) and partonomy (parts of behavior) approaches. Then, we offer a list of important exemplar behaviors based on the extant literature. Finally, we introduce the articles in the issue.