This introduction to the theory of feedback control systems covers the whole of control theory, unifying various relevant topics in a single volume. Although the material of the book is essentially mathematical, there is minimal emphasis on the technical mathematical niceties hardly needed to generate insights about control systems. Much of this second edition has been rewritten to take account of recent developments in control theory and how it is understood. Successful features have been retained from the first edition including the uniform treatment of both continuous-time and discrete-time systems, the inclusion of a wide range of topic and the provision of problems with answers making it ideal in format and content for undergraduates and graduates in Engineering Science.