This is an unusual book. It is a cooperative endeavor of authors from the areas of entrepreneurship and industrial and organizational psychology (in short, I/O psychology)—to our knowledge, it is the only book of this kind. Amajor goal of this book is the promoting of closer ties between the fields of I/O psychology and entrepreneurship. The basic rationale behind this goal can be stated succinctly: Increased cooperation between the two fields can be highly beneficial to both. In particular, we believe that the findings, methods, principles, and theories of I/O psychology can assist entrepreneurship in answering several of its most basic questions. Conversely, we suggest that the field of entrepreneurship, with its focus on new ventures, can provide I/O psychology with a novel and potentially valuable arena for testing and extending its findings and theories, most of which have been developed in the context of large, mature organizations.