We describe an architecture for the presentation of the digital content of the Hellenic Dissertations database, consisting of about twelve thousand records and two million pages. Our architecture is based on a flexible service registration and discovery mechanism, which can be used to reconfigure the Presentation System even at runtime. Services are responsible not only for presentation but also for various document conversions, format transformations, authorization policies enforcement and watermarking. The architecture encourages modular programming, by allowing services to cooperate.