Uncertainty is an unavoidable and essential ingredient of almost all applications of forensic science. Traces may carry information on who or what left them, by which activity they arose, and several other questions. In many cases there is no way to uniquely identify the only possible source or activity. This means that, while these forensic traces can reduce our uncertainty, they cannot be expected to eliminate it. Probability theory and statistics are mathematical disciplines that are concerned with uncertainty in many different ways. It is, therefore, to be expected that probability theory and statistics are crucial for understanding the philosophy, theory, and practice of forensic science. This book offers an in-depth discussion about what the mathematical disciplines of probability theory and statistics can contribute to forensic science, and more specifically about the interpretation of evidence.