This book serves as an introduction catalogue to some of the many facets of geometrical and other patterns. It is informal, and the intended audience spans several fields. The book might be used by students, graphic artists, illustrators, scientists, artists, laypeople, programmers or anyone fascinated by optically provocative art. The Pattern Book combines old and new ideas - with emphasis on the fun that the true pattern lover finds in doing, rather than in reading about the doing! The book is organized into three main parts: Representing Nature (for those patterns which describe or show real physical phenomena, eg. visualizations of protein motion, jellyfish, etc), Mathematics and Symmetry (for those patterns which describe or show mathematical behaviour, eg. fractals), and Human Art (for those patterns which are artistic works of humans and made without the aid of a computer eg. Moslem tiling patterns). A comprehensive glossary is included to help ease readers into technical or unfamiliar waters.