This text provides a comprehensive introduction to the use of frequency domain and polynomial system design techniques for a range of industrial control and signal processing applications. The solution of stochastic and robust optimal control problems is considered, building up from simple single-input problems and gradually developing the results for multivariable design of the later chapters. In addition to cataloguing many of the results in polynomial systems needed to calculate industrial controllers and filters, basic design procedures are also introduced which enable cost functions and system descriptions to be specified so that industrial requirements are satisfied. New material in this edition includes the analysis of multi-degrees of freedom controllers and time-varying control and signal processing problems, plus an extension of the linear system concepts to the control of non-linear processes using both multiple model concepts and the link to time-varying optimal control solutions.