After an overview of major scientific discoveries of the 18th and 19th centuries, which created electrical science as we know and understand it and led to its useful applications in energy conversion, transmission, manufacturing industry and communications, this Circuits and Systems History book fills a gap in published literature by providing a record of the many outstanding scientists, mathematicians and engineers who laid the foundations of Circuit Theory and Filter Design from the mid-20th Century. Additionally, the book records the history of the IEEE Circuits and Systems Society from its origins as the small Circuit Theory Group of the Institute of Radio Engineers (IRE), which merged with the American Institute of Electrical Engineers (AIEE) to form IEEE in 1963, to the large and broad-coverage worldwide IEEE Society which it is today. This second edition, commemorating the 75th anniversary of the Circuits and Systems Society, builds upon the first edition's success by expanding the scope of specific chapters, introducing new topics of relevance, and integrating feedback from readers and experts in the field, reflecting the evolving landscape of Circuits and Systems alongside the evolution of the professional society. Many authors from many countries contributed to the creation of this book, working to a very tight time schedule. The result is a substantial contribution to their enthusiasm and expertise, which it is hoped readers will find both interesting and useful. It is certain that in such a book, omission will be found, and in the space and time available, much valuable material had to be left out. It is hoped that this book will stimulate an interest in the marvelous heritage and contributions of the many outstanding people who worked in the Circuits and Systems area.