There is an increasing demand for man-made dynamical systems to operate autonomously in the presence of faults and failures in sensors, actuators or components. Fault diagnosis and health monitoring are essential components of an autonomous system. Hence, a high demand exists for the development of intelligent systems that are able to autonomously detect the presence and isolate the location of faults occurring in different components of complex dynamical systems. Fault Diagnosis of Nonlinear Systems Using A Hybrid Approach focuses on developing a fault diagnosis methodology that enables on-line health monitoring of nonlinear systems and off-line monitoring purposes.