Knowledge, communication, action - these are the concepts central to all of Habermas's thought. As a philosopher, he is concerned with the rational connection of these concepts. As a sociologist, he is prepared to analyze with care the distortion of human interaction caused by existing social and political institutions.
"It is not altogether easy to assess the work of a scholar whose professional competence extends from the logic of science to the sociology of knowledge, by way of Marx, Hegel, and the more recondite sources of the European metaphysical tradition ... The baffling thing about Habmermas is that, in an age when most of his colleagues had painfully established control over one corner of the field, he has made himself the master of the whole, in depth and breadth alike." – Times Literary Supplement