For centuries man lit his night with an oil lamp that created only about 1/10th of a lumen per watt (a very small amount of light produced for the expenditure of a standard unit of energy). Then in the late 19th century the incandescent light bulb was invented and that eventually provided about 16 lumens per watt. In the late 1930s the fluorescent lamp became a reality and gave us an amazing average efficacy of about 70 lumens per watt. Now in the early 21st century still another revolutionary development is taking place – light emitting diodes (LEDs) are or will soon give us 300 lumens per watt. Think about the amount of change in the way we have lit our homes, offices, stores, factories, and streets in just the last 20-30 years. It is nothing short of astonishing and you can bet that more change is on the way in how we light the way we live.