"The Method of Coordinates" is one volume in a series of books that present basic mathematics in a clear and simple form. The book describes a way of transferring images into formulas, describing pictures by numbers. The content is fundamental to the study of calculus and other mathematical topics. All through this volume, one finds a careful description of the step-by-step thinking process that leads up to the correct definition of a concept or to an argument that clinches in the proof of a theorem. High school students or teachers, reading this book will learn an enormous amount of good mathematics. More importantly, they would also get a glimpse of how mathematics is done.