Mirrors and lenses are an inescapable part of our modern lives, yet their study goes back to the ancient Greeks. Legend has it that the geometer Archimedes designed a system of reflecting mirrors to set enemy ships afire during the siege of Syracuse. Observations of astronomical phenomena were made possible with the invention of telescopes. Eyeglasses assisted in correcting vision defects. Today, CD players use optical systems for playback, and barriers in computing speed and storage are being broken by using optical instruments instead of magnetic ones.
From the moment in the morning when you start to primp and clean in front of your mirror, to when you sit down to enjoy some cable TV, to when you load your favourite CD into your stereo to help you fall asleep at night, mirrors and lenses are at work all around you.