There is currently widespread interest in applications of renormalization methods to various topics ranging from fluid turbulence to fluctuations in the stock market. This book is unique in demystifying this material for non-specialists. I think this book is the best introductory textbook on techniques of renormalization available. It will be a delight to read for anyone who is encountering the topic for the first time and is wishing to exploit the methods to pass an exam or in one's field.