Knowledge has played a significant role on human activities. Data Mining is the process of knowledge discovery where knowledge is gained by analyzing the data store in very large repositories, which are analyzed from various perspectives and the result is summarized into useful information. Due to the importance of extracting knowledge/information from the large data repositories, data Mining has become a very important part of engineering affecting human life in various spheres directly or indirectly. Data Mining have various applications and these applications have enriched the various fields of human life including business, education, medical, scientific research, etc. Objective of this book is to discuss how the Data Mining technique is helpful in CRM so that necessary conclusion can be derived.