Chapter I introduces the basic principles of transistors. In the following chapters the applications of these devices in a wide variety of circuits are discussed. Chapters 2 to 5 inclusive discuss the ways in which transistors and integrated circuits can be used for the amplification of signals. In chapters 3 and 4 the gain of an amplifier has sometimes been expressed as 20 log10 (the voltage gain) dB even when the input and output impedances are (probably) not equal. This is the usual practice when considering Bode diagrams and the stability of feedback amplifiers and does lead to some simplification of problems. Chapters 6 and 7 are concerned with the methods employed to generate repetitive waveforms. Sinusoidal waveform generators are the subject of Chapter 6, while Chapter 7 deals with the generation of non-sinusoidal waveforms. The important topic of electrical noise is then considered in Chapter 8. Chapters 9, 10 and 11 then deal with phase-locked loops, active filters and power supplies. In a few places, most notably in Chapter 10, some simple use of the Laplace transform has been made. The reader who is not familiar with this technique should merely regard S as being equal to jw. In many points in the text an indication has been given to the design of a circuit as a basis for the design of more complete systems. The book has been written on the assumption that the reader already possesses a knowledge of Electronics, Electrical Principles and Mathematics of the standard reached by the level III units of the Business and Technician Education Council's scheme for electrical, electronic and telecommunication technicians. Many worked examples are provided in the text to illustrate the principles that have been discussed and a number of exercises are provided at the end of the book. Answers to the numerical exercises are also given.