Although our primary focus is Brazilian antitrust, we accept it as being deeply tangled with the international debate. This book argues that antitrust doctrine has not consolidated a concept of competition that is both (i) legally coherent (with antitrust statutes and decisional criteria) and (ii) socially adequate (to competition empirical manifestation and its modern imaginary). It asks three questions to illustrate this: what has been done? what is missing? what could be implemented? Taking Brazil as a case study, it also explores the question from a global perspective.