The last decade has seen unprecedented advances in network and distributedsystem technologies, which have opened up the way for the construction of globalscale systems based on completely new conceptions of computation and sharing of resources. The dream of integrating unlimited levels of processing power, unlimited amounts of information, and an unlimited variety of services, and o.ering the entire package in a reliable and seamless fashion to widely distributed users is quickly becoming reality. As Digital Libraries move towards more usercentric, pro-active, collaborative functionality and application diversity, they should be among the first to take advantage of such environments. The long-term vision of the field for creating Dynamic Universal Knowledge Environments calls for intensive computation and processing of very large amounts of information, hence, the needs for the appropriate distributed architecture are pressing.