This book takes readers on a tour of the LED evolution, beginnig with a brief history of the effort to enable the device that generates light through modern organic LEDs. It reviews the fundamentals and principles of light prior to a detailed explanation of how LEDs generate different colors. After forming this basic foundation of knowledge, the book examines the key of LEDs in lighting and communications. It then discusses the latest opportunities and advancements in high brightness (HB) LED technology, solid state lighting, and handheld electronic applications.