An adaptive system for linear systems with unknown parameters is a nonlinear system. The analysis of such adaptive systems requires similar techniques to analysis for nonlinear systems. Therefore it is natural to treat adaptive control as a part of nonlinear control systems. "Nonlinear and Adaptive Control Systems" treats nonlinear control and adaptive control in a unified framework, presenting the major results at a moderate mathematical level, suitable to MSc students and engineers with undergraduate degrees. Topics covered include introduction to nonlinear systems; state space models; describing functions for common nonlinear components; stability theory; feedback linearization; adaptive control; nonlinear observer design; backstepping design; disturbance rejection and output regulation; and control applications, including harmonic estimation and rejection in power distribution systems, observer and control design for circadian rhythms, and suppression of flutters in aircraft. "Nonlinear and Adaptive Control Systems" is of interest to postgraduate students and senior graduate students in control engineering, and in other engineering disciplines relating to dynamic modelling and control, including electrical and electronic engineering, aerospace engineering, and chemical engineering, as well as researchers and engineers working on nonlinear and adaptive control.