what makes a property intrinsic? What exactly does the intrinsic/extrinsic distinction rest upon, and how can we reasonably justify this distinction? These questions bear great importance on central debates in such diverse philosophical fields as ethics (What is the nature of intrinsic value?), philosophy of mind (Does mental content supervene on internal bodily features?), epistemology (Can intrinsic duplicates differ in the justification of their beliefs?) and philosophy of science (Do the causal powers of an object depend on its extrinsic features?) - to only name a few. Given the central relevance of the intrinsic/extrinsic distinction to philosophical research, a collection of pertinent essays on the topic is an essential addition to the literature. It helps to identify more clearly the problems and arguments that are at stake. The anthology provides a comprehensive overview of central facets of the debates, including both crucial earlier and important new contributions by leading philosophers. As such it constitutes an indispensable component of any serious study of the topic.