Safety is an important issue today. International standards such as ISO and IEC advocated goal-based procedures of designing safer systems. This assumes safety goals are explicitly established.This book is a methodological approach to the goal-based safety design procedure that will soon be an international requirement. Case studies illustrate the methodologies presented. The book: presents accident statistics and safety goals; describes abnormal event enumeration for the target system; develops risk reduction mechanisms; discusses probabilistic risk assessment (PRA) models; presents conventional materials for basic event quantification; shows how to calculate safety criteria from the PRA models; evaluates uncertainties of point estimates of safety criteria; and considers how external event quantification can expand the scope of PRA.This book will interest senior undergraduates, postgraduates and researchers in this field, and reliability engineers, industry practitioners and regulatory authorities.