We are all familiar with the everyday notion of two-sided symmetry, as viewed for example in the external form of the human body. But in its broadest interpretation symmetry is a property which involves regularity and repetition. In this sense symmetry can be found everywhere, especially in science and art. The aim of this book is to present selected examples of symmetry, drawn from a wide variety of topics, in a way that will be understandable to students and teachers of mathematics as well as to the interested layman.