Book excerpt: Visible light has an inescapable presence all around us. We have generated light from prehistoric times using a variety of techniques. In modern times, we mainly produce illumination through electrical means. There are interesting historic anecdotes and fascinating scientific facts behind the various modern techniques for generating light.This book attempts to describe the stories and technologies related to many light sources — some common, some less so. Described in a more-or-less chronological fashion, the book looks at developments from Edison and Swan's invention of the incandescent lamp, through lasers, to LEDs, and more. While the main focus is on sources of visible light, a number of devices that produce invisible radiation are also covered for the sake of completeness.The book provides a holistic view of common and uncommon light sources from both historic and technical perspectives, to help readers place more modern developments in the context of what came before, and how. This book will be of benefit to all who are interested in optical sciences, especially in the generation, detection or use of electromagnetic radiation.