People have always been fascinated with their image, first visible by looking at one's reflection in water. Later, smooth volcanic rock served this purpose, only a limited quantity (and a rather approximate quality) being availabe. There are even Biblical references to mirrors, one stating that introspection is much like the limited concept of those who "look into a glass darkly" ; another cites the folly of a man who looks at his own face, then walks away, forgetting altogether what he has just seen!
The first man-made mirrors were probably Syrian. A glass bubble was first blown, then used as a mold into which molten metal was then poured. The cooled metal had a relatively slick surface, which could then be polished to a high sheen. As glass-making was perfected, so was mirror-making. The "modern" version: one side of a glass pane is painted with a metallic base, permitting reflection on the other side.
Mirrors serve multiple purposes other than just being able to see one's reflection. They are used by both science and magic, exist in multiple forms (direct, convex and even concave) and have even been incorporated into the ancient art of Feng Shui and some healing rituals. The concept of mirrors has invaded folklore (The wicked queen's number one question in "Snow White?") and psychology. (A concept of critical self-development in infancy is known as "mirroring.")
For more information, see the following references.