There is a great need for digital libraries that are flexible, scalable, and reliable. Few such systems exist. Little is known about how to build them. This thesis addresses these problems by enhancing a prototype digital library system with the aim of making it more flexible, scalable, and reliable. We hypothesize that: 1) adding a new (user information) layer and maintaining weak coupling in the design of a digital library system can help achieve system flexibility; 2) optimizing network connection usage and facilitating distribution of computation and disk operations in system design can help achieve system scalability; and 3) applying good software processes can help university students produce a very reliable system. Approaches based on the above hypothesis were used in the project of Reengineering the MARIAN System in Java. The results of the project and experiments verified the correctness of the hypothesis. The results of this thesis may help inform future digital library design and implementation projects to produce flexible, scalable, and reliable systems. / Master of Science