Tiziano Raffaelli (Pisa 1950) was a widely esteemed scholar in the field of the history and methodology of economics, who died suddenly in January 2016 while still in the midst of working and of developing projects for new lines of research. He was a philosopher of science by formation and a historian of economic ideas by professional choice, with interests covering a vast area, ranging from the 18th to the 20th century and from Europe to the US. Where he left an indelible mark, however, was in his interpretation of Alfred Marshall’s economic theory and its reverberations through Keynes on the one hand, and the Cambridge school of industrial economics on the other. Raffaelli’s research in this field offered a completely new view of the core and meaning of Marshall’s work and of its relevance for 21st century social scientists. In the process, it stimulated a new and fruitful research program in Marshallian economics. This volume consists of two parts. The first is devoted to illustrating the above-mentioned changes in the understanding of Marshallian economics and Raffaelli’s role in bringing them about. The second part offers a collection of essays documenting some more recent developments in fields related to Marshall and his influence, including welfare economics and industrial organization, Marshall’s legacy in Cambridge economics, the Chicago school, and beyond. The contributors to this volume range from leading senior scholars in the field to exceptional young scholars, and their contributions illustrates a myriad of ways in which the new view of Marshall inspired by Raffaelli’s work influences our understanding of the history of economics from the late 19th century onward. This book will be of international interest to scholars working in the history of economic thought, and will also appeal to philosophers of science, methodologists, intellectual historians, and those who specialize in industrial organisation.