Unmanned aerial vehicles (UAVs) offer a means of gathering intelligence and carrying out missions. The benefits are considerable in terms of cost, efficiency, and reduced pilot risk. To complete a mission efficiently and with a high level of safety and security: the flight control system must be robust against model uncertainties and external disturbances; an efficient fault detection and isolation system; the flight control and guidance system should be reconfigurable depending on actuator fault occurrence or aircraft damage, and able to avoid obstacles. This book addresses all of these aspects with a practical approach following three main requirements: applicability in real-time; computational efficiency; and modularity. The text provides: an overview of fault-tolerant flight control techniques; the necessary equations for the modeling of small UAVs; a complete nonlinear fault detection and isolation system based on extended Kalman filters; a nonlinear flight control and guidance system.