A practical technical handbook on *sûreté de fonctionnement*—dependability in engineering systems. The work presents core concepts and methods for understanding, assessing, and improving the dependability of complex technical systems, including reliability, availability, maintainability, safety, fault tolerance, and risk analysis. Intended for engineers, researchers, and advanced students, it offers a structured reference for modeling system behavior, identifying failure mechanisms, and applying dependability principles across design, operation, and maintenance contexts. As a French-language reference from the 1990s, it reflects established approaches to system dependability and remains useful for readers seeking a formal overview of the field.