The engagement to which the title of this book refers needs a few words of explanation. The texts below are critical essays on a variety of thinkers of the post-war period. In disciplinary range, these figures include historians of different fields, from antiquity to the recent past; sociologists who have taken the set of human societies as their subject; philosophers and critics of the political and cultural problems of modernity. In geographical setting, the writers involved have worked in what is still the principal region of intellectual production at large: the four leading countries of Western Europe -- German, France, England, Italy -- and the United States. If the contrasts in interest and outlook among the individual figures discussed are often wide, the ideas of all pass, in one way or another, by the crossroads between history and politics. This is the area that has taken up most of my intellectual life, and explains the cast of this volume.

The selection of authors considered here is partly a product of circumstance, as opportunity or solicitation arose. But it also corresponds to a temperamental choice. Out of the various possible motives for writing about the work of others, one combination has typically prompted me. The principal impulse behind these essays is one of admiration. Without this, none would have been written. In a general intellectual survey, I can be as hostile or dismissive -- to the point of destruction -- as anyone. The condition of a specific engagement, however, has always been respect. But I also need to feel a significant dissent. Without that, the precipitant of the form most natural to me seems to be lacking. So while this book is a record of different admirations, it is not an inventory of affinities or influences. The one exception is the piece on Isaac Deutscher, written as an introduction to a posthumous collection of his essays, rather than as a critical assessment of his major work, and so in a category apart. Generally speaking, I find it difficult to write about those to whom I feel, in one way or another, too intellectually close: which explains why, for example, this volume contains no appreciations of Eric Hobsbawm . . .