Network technologies have helped to lower many of the geographical barriers that impede access to information resources, but other obstacles have appeared in their place: one is the heterogeneous use of resource descriptions; another, more serious, is the lack of resource description at all. Resource description varies depending on the structure, type and content of resources; it also varies with the interests of the information keepers responsible for the management of these resources. A further consideration in resource discovery is the cross-domain information needs of users who require access to information about relevant resources irrespective of where they are located, how they have been stored or by whom. With the current enabling technology, the more complex needs of users nowadays can be met: querying more than one domain-specific information system in parallel while information managers seek to have a system that enables access to separately managed collections in-house. Example of initiatives that have been developed to encourage timely dissemination of scholarly information is the Open Archive Initiative (OAI).