The growing social and economic significance of expertise is reflected in popular suggestions that we are moving into a post-industrial ''knowledge society''. The subject of expertise is becoming recognised in a range of scholarly disciplines ranging from science and technology, psychology, computing and artificial intelligence through to management and organisational behaviour. Exploring Expertise brings together some of these diverse understandings of the character and implications of expertise, and demonstrates through a set of empirical case studies how expertise means different things to different groups, how it is constructed differently in different settings, and the consequences of this process for relations between ''members'' of the knowledge society and those ''on the outside''. The book includes case study material ranging from a hospital ward to a factory to a nuclear weapons facility.