The ability to manipulate light dates back to ancient times. The understanding of the nature of light, which involved debates over whether it is composed of waves or particles, began in the 1500s and 1600s. The discovery of and the elaboration of principles needed to design optics with confidence began in the early 1800s. It seems quite likely that reflections in calm lakes and ponds were seen and wondered at since the dawn of human existence, perhaps millions of years ago, but no trace remains. The earliest optical devices we have found are stone and obsidian mirrors from the Bronze Age in Europe and the Middle East. It is likely that at about the same time people noticed their reflections in the blades of metal swords, axes and armor if they were highly polished. Flat mirrors reflect light at the same angle as it is incident at, and the formation of an image takes place in the eye of the beholder. A mirror can concentrate light if its surface is made concave. There are Greek accounts…