I found the title of this books really compelling, and so decided to read this book. In it, for each equation, the chapter starts out on the applications that are easier to understand. The first chapter is about Pythagoras’s theorem. For better understanding of the application, the book starts with telling us a short summary of the equation’s history. Then, it moves on to application, which is easy to understand (e.g. using Pythagoras to prove sine and cosine rule), and then moves on to applications that have greater impact (usually harder to understand as well). It was very interesting to know that a basic theorem like this very important to the invention of the coordinate system we studied in maths class everyday. It is also the underlying mechanism of triangulation used in everyday GPS. However, the writer dedicated the end of the chapter to Euclidean geometry, which is really abstract, and difficult to understand. I feel that the book relates what we learn in class more to the real world giving each topic more weight and make it more interesting.