In this book, Erica Beecher-Monas develops an interdisciplinary approach, combining legal and cross-disciplinary scientific considerations, to provide a heuristic framework within which to assess whether expert evidence meets the requirements of intellectual due process. It provides a valuable introduction for lawyers to the methodological issues that need to be addressed in understanding whether a piece of proposed expert evidence can be classified as 'scientific.' This book marks a welcome re-assertion, on firm epistemological grounds, that the use of expert evidence represents part of the rationalist endeavor of accurate fact determination, in support of the moral authority of law.