ABSTRACT
In this introductory chapter the aim is to introduce the physics involved in the production of microwaves using free electrons and to discuss some of the types of microwave sources that exist. Later chapters written by international authorities in their fields will focus in more detail on individual types of microwave source and their characteristics. Alan Cairns in his chapter similarly introduces the twin theme of this book, namely the application of high power microwave sources, particularly to plasma heating and that theme is then again treated in greater detail in a series of chapters on the application of these sources.
