Book excerpt: Presents methods and techniques for assessing the reliability, availability, maintainability or safety of industrial systems. Describes the history of dependability concepts and methods and also defines the main concepts and principles of predictive analysis used. The second section is a detailed description of principles and methods. The third deals with the specific methods used in the fields of human factors, mechanics, software and safety assessment. The last section lists the main computer programs developed to assess dependability and common cause failures.