Using clear tutorial examples, this fully updated new edition concentrates on explaining and illustrating the concepts that are at the heart of control theory. It seeks to develop a robust understanding of the underlying principles around which the control subject is built. This simple framework is studded with references to more detailed treatments and also has interludes that are intended to inform and entertain. The book is intended as a companion on the journey through control theory and although the early chapters concentrate on fundamental ideas such as feedback and stability, later chapters deal with more advanced topics such as state variables, optimisation, estimation, Kalman filtering and robust control.