As markets become increasingly saturated and competition intensifies, it is becoming more challenging for companies to acquire new customers. Therefore, it is crucial to retain existing customers for future purchases. On the other hand, studies have shown that about 25% of customers have a potential reason to complain, but only about 5% actually voice their complaints, and only half of that 5% are satisfied with the resolution of their complaint. Since these are existing customers, it makes sense to discuss complaint management as a tool for customer retention. Especially since the literature on customer retention hardly addresses complaint management. The aim of this book is to explore how complaint management contributes to customer retention and how effective complaint management should be designed.