My decision to re-publish the essays in this book requires an explanation, perhaps even an apology. The essays have been selected and brought together on the strength of their common theme, which is that of the inter-relation of history and the social sciences. Indeed, the object of the publication is not to salvage a number of articles and lectures from oblivion, but to re-assert anew their point of view. In anno domini 1970 this re-assertion may turn out to be, to say the least, unpopular. Readers familiar with current intellectual fashions will find it only too easy to recognize and to docket this collection as ‘positivist’ or ‘scientistic’, and there is no need for me to remind them of the opprobrium which these dockets nowadays carry. Except for Marxists, most historians writing about the philosophy of history, most philosophers concerned with the methodology of historical and social study, and even some influential social anthropologists, have in recent years ranged themselves against the supposed fallacies of ‘scientism’. They accept, however unconsciously, the idealistic dichotomy of ‘physical’ and ‘humanistic’ studies, or that of pure and practical reason, and consequently decry all attempts to use the methods of natural sciences in the study of history or of human affairs in general. It matters not that ‘positivist’ and ‘scientistic’ assumptions in fact underlie, as they must do, all current work of historical and sociological discovery.