This book aims to help students by illustrating, by means of a series of worked examples, the fundamental steps underlying an understanding of control principles. Attention is restricted to the important basis which comes from continuous linear single input single output systems. The approach is progressive starting with the mathematical methods used most frequently in the study of single input single output systems. Because much of the teaching of control is necessarily done in terms of a mathematical model of a device or plant, examples of the formation of deterministic models of simple physical systems follow. Manipulation of these models leads to the introduction of control and the use of both time domain and frequency response methods. In particular the assessment of the stability of closed loop negative feedback control systems forms the central feature of this. Such a text as this cannot be exhaustive either in terms of material covered or in its range of examples. It is hoped that in its limited length and fundamental context it gives wide accessibility to students of many engineering disciplines and assists them to overcome the early stumbling blocks of representing physical systems by mathematical equations and the subsequent manipulation of these in a dynamics and control context. The further development of the subject relies on a firm foundation of this material.