From the past, customers who are satisfied with using a product or service, introduce it to others. Business owners use this potential of their satisfied customers and the word-of-mouth advertising tool for marketing, turning their customers into sellers of their products and making a profit for them by using modern tools. This process of attracting customers and making profit for the referrer is called “referral system” (referral/affiliate system). Having such a system is one of the best ways to develop the business. In this book, this concept and its function are described in simple language and with a smart view in order to use it in your business. This means looking at existing standards from new angles and using your business’s best approach based on your unique circumstances.