He identifies a series of ‘schools’ and evaluates their contribution, supplying in each case a careful analysis, informed by the sociology of knowledge, of the work of its leading theorists. His final assessment draws on the critical theory of Habermas, arguing that social theorising is essentially practical; a matter of the construction, criticism and comparative ranking of ideologies, and that theorists should therefore consider what it makes sense for them to do or say, given their circumstances and the problems they address.