This book stimulates contributions that explore the concept of 'progress' and its economic achievements in Progressive Era American Economics (1890-1920). During this period, many economists and social reformers put forth the idea of 'progress' to radically transform the American economy and society in order to reduce different kinds of inequalities and conflicts among social groups. The notion that American academia must serve as the headquarters for developing 'progress' became particularly important during this era.When studying this period, economists often take for granted what 'progress' and being progressive meant, failing to question its possible implications. Too often, the scientific debate rests on a clear separation between the allegedly conservative ideas of American heirs of the Classical school and the progressive ideas of the "new" wave of American economists influenced by the German Historical School. Such a stance tends either to simplify reality or underrate key features of economists' mindsets of the period.This book fills a significant gap in the literature on the history of economic thought by investigating scientific controversies about 'progress' during the Progressive Era. It examines the meaning of 'progress' in Progressive Era American Economics, confronting the different perspectives of social scientists of the period and challenging conventional interpretations that oversimplify the intellectual landscape of this transformative era.Covering the history of economic thought, Progressive Era studies, American economic history, intellectual history, and the philosophy of economics, this book is essential reading for students, scholars and researchers interested in economics and history.The chapters in this book were originally published as a special issue of The European Journal of the History of Economic Thought.