In the distant past, a human being noticed their reflection in a body of water and that the reflection was of their own body. It was, perhaps, love at first sight. Over the course of several millennia, humans learned how to make that reflection portable, first by polishing stone and metal, then by bonding a metal to the back of a clear glass or plastic. As the reflections became clearer and brighter, mirrors were applied to more than self-inspection: for extended vision, via periscopes, telescopes, microscopes, and cameras; for communication, via heliographs, photophones, and the mirror galvanometers of undersea telegraph cables; for amusement, via kaleidoscopes and stage illusions; for energy, via solar furnaces and sunlight-propelled spacecraft; and for other purposes, via many additional ingenious devices. This book presents the story of the construction and use of mirrors for work and play.