Forensic metrology is the application of scientific measurement to the investigation and prosecution of crime. It provides a framework for the performance and critical evaluation of all forensic measurements. It enables forensic scientists to better develop, perform and communicate forensic measurements; lawyers to better understand, present and cross-examine the results of forensic measurements; and judges to better subject testimony and evidence based on forensic measurements to the appropriate gatekeeping analysis. This book sets forth the metrological framework required to reach sound conclusions based on measured results and the inferences those results support.