To aid researchers in obtaining, organizing and managing biological data, we have developed a sophisticated digital library system that utilizes advanced data mining techniques. Our digital library system is centralized with Web links to publicly accessible data repositories. Our digital library is based on a framework used for conventional libraries and an object-oriented paradigm, and will provide personalized user-centered services based on the user?s areas of interests and preferences. To make personalized service possible, a "user profile" that represents the preferences of an individual user is constructed based upon the user?s past activities, goals indicated by the user, and options. Utilizing these user profiles, our system will make relevant information available to the user in an appropriate form, amount, and level of detail with minimal user effort.