This course examines the nature of scientific evidence, the recent revolution in the scientific gate-keeping role for judges following the Supreme Court's decision in Daubert, and a variety of controversies regarding the admissibility and weight of particular types of expert testimony. After covering the basic legal tests for the admission of scientific evidence, we will proceed to examine several recurring topics in the law of expert testimony. We will give special attention to questions of scientific identification (common in criminal cases) and questions of scientific proof of causality (common in products liability and toxic tort cases). We will also consider common types of expert evidence from the behavioral sciences, including syndrome evidence and evidence regarding defects in human memory. In each instance we will examine the bases for claims of expertise and survey how these claims have fared in the courts.