Focusing on the Takagi Sugeno (TS) fuzzy model, this volume provides a range of methods and tools to design observers for nonlinear systems. Readers will find an in-depth theoretic analysis accompanied by illustrative examples and simulations of real-world systems.Introduction.- Takagi-Sugeno fuzzy models.- Stability analysis of TS fuzzy systems.- Observers for TS fuzzy systems.- Cascaded TS systems and observers.- Distributed TS systems and observers.- Adaptive observers for TS systems.