To most people, mathematics means working with numbers. But as Keith Devlin shows in *Mathematics: The Science of Patterns*, this definition has been out of date for nearly 2,500 years. Mathematicians now see their work as the study of patterns: real or imagined, visual or mental, arising from the natural world or from within the human mind. Using this basic definition as his central theme, Devlin explores the patterns of counting, measuring, reasoning, motion, shape, position, and prediction, revealing the powerful influence mathematics has over our perception of reality. Interweaving historical highlights and current developments, and using a minimum of formulas, Devlin celebrates the precision, purity, and elegance of mathematics.