Dependability analysis is the recent approach to performance evaluation of contemporary systems which tries to cope with new challenges that are brought with their unprecedented complexity, size and diversity. Especially in case of computer systems and networks such evaluation must be based on multidisciplinary approach to theory, technology, and maintenance of systems which operate in real (and very often unfriendly) environments. As opposed to classic reliability which focuses mainly on technical aspects of system functioning, dependability studies investigate the systems as multifaceted and sophisticated amalgamations of technical, information and also human resources. This monograph presents selected new developments in such areas of dependability research as mathematical models, evaluation of software, probabilistic assessment, methodologies, tools, and technologies. Intelligent and soft computing methods help to resolve fundamental problems of dependability analysis which are caused by the fact that in contemporary computer systems it is often difficult to find a relation between system elements and system events (the relation between reasons and results) and it is even more difficult to define strict mathematical models with analytical relationships between such phenomena.