This book tells the story of the advent, study and development of electronics which began just prior to the beginning of the 20th century. It covers the more important inventions that resulted from discoveries, research and innovation. Introduced are the inventors who claimed these discoveries and developments for themselves, for the teams with which they worked and for the companies by whom they were employed. Many of these inventions were of amplifiers and switches employing the properties of semiconductors that began to be understood in the 1920s. The early semiconductor devices include the rectifier and and the transistor. The important types of transistor invented are the point-contact, the junction and the field-effect transistor. The transistor that resulted in an implosion of electronic circuits, i.e., the reduction in size, energy to operate and cost to manufacture, is the metal-oxide-semiconductor field-effect transistor, the MOSFET. This transistor employing the planar process, became important in the integrated circuit (microchip) and in the microprocessor (the computer central processing unit on a chip). Patents are recognized and explained with text and numerous line drawings. A glossary is provided with definitions specific to their application in this book.