This article asks why it is so difficult to find a place for Raymond Aron among sociologists, even though he is consensually regarded as one of the most important contributors to the development of political sociology and to the analysis of the democratic political regjmes of his day. The author examines the foundations of Aron's 'political sociology' in terms of (a) Aron's intellectual development and (b) the French intellectual scene from the 1940s to the 1980s (including the conflict with Sartre and Merleau-Ponty over Soviet totalitarianism). Also discussed are Aron's intellectual roots in the French philosophical tradition (Montesquieu and Tocqueville), his analysis of German thought in the late 1930s (especially the influence of Max Weber), and the fundamentals of his philosophy of history. In the second part the author looks at Aron's critical analyses of totalitarianism and contrasts the specifics of his approach with some frequent themes in the theories of totalitarianism, namely the so-called uneven distribution of fear and 'hidden' (illegal and illegitimate) exclusion. In conclusion the author interprets Aron's 'pessimist dialectics' (disenchantment with the idea of progress) as a vital stimulus for the study of social and political issues today.