Most of the component parts of this volume started as separate papers written at various times and in various contexts. What these papers had in common was that they were all concerned with one or other of the three (or perhaps four) major turning-points in the history of economic thought, associated with the names of Smith, Jevons, and Keynes (and, in a rather different way, with that of Ricardo). As I reconsidered and revised these essays, I became more and more interested in the nature and variety of the changes and processes of which these major turning-points, 'shifts in research programmes', or 'revolutions', consisted, and in how far, and in precisely what sense, they can be said to have represented 'progress' in the subject. Therefore, in the course of being revised, rearranged, and rewritten, in most cases quite comprehensively, these papers have developed interconnections and inter-relations in respect of their common concern with these turning-points, or processes of major change, or 'revolutions'. Comparisons and contrasts have suggested themselves between the different cases. So on one level the chapters in this volume may be read--by those less interested in their methodological aspects --simply for such contributions as they may make to the study of particular episodes, and of particular economists and their works. But they may also be regarded as attempted contributions to the study of the three or four major changes, turning-points or transformations in the history of political economy and economics, and of the processes by, and senses in which, 'progress' might be held to have come about.
Finding a suitable title has presented considerable difficulties because the subject-matter, or processes, with which this book is centrally concerned, are so complex and imprecise, blending general qualities with particular historical characteristics. The first question to be answered was: what word, or brief caption, sums up best the profound and variegated changes in economic theorising and political economy