Supervenience is one of the 'hot discoveries' of analytic philosophy, and this collection of essays on the topic represents an examination of it and its application to major areas of philosophy. The interest in supervenience has much to do with the flexibility of the concept. To say that x supervenes on y indicates a degree of dependence without committing one to the view that x can be reduced to y. Thus supervenience is a relationship that has the potential of replacing the traditional notion of dependence, while performing at least part of the function reductive relationships were supposed to fulfil. Moreover, since it is a topic-neutral concept, supervenience has a wide range of applicability.