This text is intended to be a populist book. With so many complex equation–filled engineering books lining the shelves of our bookstores, perhaps you are wondering whether the science of microwaves and RF is ready for a text that can be understood by those who do not speak Latin or wear black robes. We believe so. The goal of a populist book is to appeal as much to the academic at a highbrow university as to the practitioner working in today’s frantic production environment. We hope you will find this text as relevant to your work of teaching others as to improving your own skills. This book is written for practicing engineers and for those who would like to become one. And these days, who can afford not to keep learning? Whether you are a student at your final year of college, an engineer in industry who has just been assigned your first RF design project, or a seasoned veteran of the magic of microwave design, we hope that you will all find something useful in these pages. Even if you are a microwave or RF industry guru with most of the answers already, our experience in writing this has been that there is still a thing or two out there that needs explaining. If you cannot find anything that seems inexplicable, then at least you will have the satisfaction of reassuring yourself that you have indeed been right all these (long!) years. We do not suggest you throw away your other excellent text books that explain semiconductor transport equations, Green’s functions, or the complex mathematics of filter design; just that this effort might make those paperweights all the more relevant. Do not misunderstand us—we do not imply that anyone can become a high-grade RF circuit and system designer without using any complex algebra. We feel strongly, however, that you do not need as much of it as some of the courses you have taken before may have included. This book and Volume I are the culmination of more than 40 joint years of teaching these topics to thousands of practicing electrical engineers from around the world. Little by little, we have extended the scope of our courses and learned the simplest ways to convey basic ideas to our audience. We have often been surprised and have found for the most part that our audience is generally not interested in obtaining guru status or academic knowledge, but interested rather in gaining an understanding of microwave and RF circuits, in gaining intuitive insight, and in applying that to their work. We hope we have captured that spirit herein. This book is not written for the expert. If anything, we have omitted specialist material (it is long enough as it is!). We often begin our courses by telling our students that if they have spent the past year characterizing the intermodulation properties of a device to design a predistorter circuit, they are probably already one of just a handful of experts in the world in that area—and they can probably teach us something. Although we hope this book will convey the background and insight to set you on the road to becoming an expert, it will not take you down the narrow and winding lanes that make you one. We have focused on discrete circuits and discrete circuit design rather than IC design, believing that only when discrete design is mastered can those techniques be applied to integrated circuits. In consciously stopping short of IC design, we have not considered many worthy topics, such as RC or AGC oscillators or complex biasing techniques. Nor have we considered integrated systems such as phase-locked loops. All these topics are worthily covered elsewhere in expert texts of their own, and rightly so. Perhaps a third volume of this series will one day attempt to simplify those topics as well, should our wives ever let us back near our computers again!