Deal comes from real cases that Noah Fleming, an American strategic marketing expert personally contacted or directed, it is another masterpiece after the best-selling book "Evergreen", which introduces ways to improve customer loyalty. He believes that establishing deeper, more lasting relationships with older customers can bring greater profits than pursuing new customers. Deal analyzes the customer’s purchasing behavior in depth, maintains the long-term purchasing power of customers, and continuously extracts the value of customers. Through the introduction of customer experience science, it analyzes the four stages of realizing the customer loyalty cycle, namely, understanding customer psychology in depth; converting potential customers into sales targets; attaching importance to customer experience, permanently attracting customers, and then achieving the ultimate goal – deal.