This course aims to present the overall approach to reliability engineering and its impact on industrial processes and systems. It introduces the key concepts of dependability (reliability, availability, maintainability, and safety) and explains how they are integrated into system design, operation, and maintenance. Particular emphasis is placed on widely used analytical tools such as Failure Modes, Effects, and Criticality Analysis (FMECA), Fault Tree Analysis (FTA), and  diagram bloc reliability DBR which are essential for identifying potential failures and assessing risks