What is Ecopreneurship? This book proposes to define Ecopreneurship in theory, as well as to increase the understanding of it in practice. Conceptually Ecopreneurship is to be found at the intersection of the entrepreneurship and the sustainability science fields, excluding social sustainability. It is constructed around the three core principles of entrepreneurship, which are redefined in order to fit sustainability requirements: eco-innovation, eco-opportunity and eco-commitment. Operationalized in terms of the three aforementioned concepts Ecopreneurship is applied to four different cases, four companies in the south of Sweden, to investigate whether their business could be deemed ecopreneurial. The analysis of the cases reveals new unexpected insights into the four companies and it also establishes the practical usefulness of the ecopreneurship framework as an analytical tool. Only with a thorough and honest conceptualization of ecopreneurship that incorporates the principles of sustainability, does environmental progress become discernible from "green-washing" when analyzing "green" companies. It is one of the central aims of this book to help make this distinction possible.