An introductory educational aid that complements the first part. It covers "modern control systems" in three chapters, namely nonlinear systems, state-space equations, and digital systems, while the first part covers "classical control systems." The analysis of nonlinear systems, in Chapter 14, is conducted using the descriptive function method, which is applied when the system has a single nonlinear element and has many practical applications. Chapter 15 covers the study of systems with state-space equations over time. This method has gained popularity because it can be applied to systems with multiple inputs, to nonlinear systems, to time-varying systems, and to digital systems, and because it offers economy of symbols and ease of use for both digital and analog computers. Finally, in Chapter 16, the reader is introduced to the analysis and design of digital control systems, after the necessary mathematical tools, namely the z-transform and difference equations, are developed.