For centuries, when shadows fell and dark of night descended, most human activities were put on hold until they could resume the following morning. Candlelight or gaslight was too expensive, too dangerous and too dim for work to continue. The light bulb, along with the steam engine, transformers, and electric generators changed the rhythm of everyday life. For everything from manufacturing to transportation to communication and beyond, power, along with reliable transmission systems, became essential. The following stories highlight these revolutionary engineering marvels and other innovations that have transformed the way we live.