Introduction, basic concepts and preliminaries -- Basic ideas, major issues and tools in the observer-based FDI framework -- Modelling of technical systems -- Structural fault detectability, isolability and identifiability -- Residual generation -- Basic residual generation methods -- Perfect unknown input decoupling -- Residual generation with enhanced robustness against unknown inputs -- Residual generation with enhanced robustness against model uncertainties -- Residual evaluation and threshold computation -- Norm based residual evaluation and threshold computation -- Statistical methods based residual evaluation and threshold setting -- Integration of norm based and statistical methods -- Fault detection, isolation and identification schemes -- Integrated design of fault detection systems -- Fault isolation schemes -- On fault identification.