Libraries today have to investigate the methods connecting the results from continuously collected customer information with their activities, policies, and procedures. In other to prevent customer secession and to obtain new customers, it is necessary to effectively offer the processes for every customer related service, that is, the contact, the reguest, satisfaction, etc. This is Customer Relationship Management(CRM). This study aims to introduce the concept, the constitution elements, and theories for importation and application of CRM, and to investigate the possibility for library application. Also, it is emphasized the necessity for new marketing strategy putting the customer value preferentially in libraries.