This book is an important contribution to ‘new evidence scholarship’, showing how mathematical probability theory provides a framework for the understanding and pursuit of factual accuracy in judicial proof. It begins by identifying factual accuracy as a major goal of juridical proof, provides an introduction to probability theory, with illustrations in gambling and statistics, before exploring a range of issues concerning standards and burdens of proof, including the difference between civil and criminal standards of proof, the variability of these standards, and whether there is a requirement that proof be detailed and not too generalised. This study provides the first sustained and systematic treatment of evidential issues, which applies probability theory to actual cases.