EULER is a European based world class real virtual library for mathematics with up-to-date technological solutions, well accepted by users. In particular, EULER provides a world reference and delivery service, transparent to the end user and offering full coverage of the mathematics literature world-wide, including bibliographic data, peer reviews and/or abstracts, indexing, classification and search, transparent access to library services, co-operating with commercial information providers (publishers, bookstores). The EULER services provide a gateway to the electronic catalogues and repositories of participating institutions, while the latter retain complete responsibility and control over the creation and maintenance of their data collections as well as the access provisions pertaining to their offerings. The talk will explain the origins of the EULER service, the legal structure of the EULER Consortium, membership structure, roles of the members, as well as the general business model. Several initiatives are currently globally underway to establish a comprehensive Digital Mathematics Library, consisting of scanned images of the whole corpus of historical works, and genuine electronic publications in mathematics. In such an environment, where several partners would on a global scale work on such a distributed scanning and preservation project, a powerful end-user discovery tool will be needed that works independently from local specialities and formats, is capable of integrated homogeneous retrieval of heterogeneous distributed sources, and is scalable to cope with the amounts of data that are to be expected. EULER has proven that its model is an optimal choice for such a discovery system. Only few adaptations seem to be necessary. Currently, EULER is in possession of two different technical options that are ready to run the EULER services: - A decentral model, consisting of special Z39.50 servers running at distributed sites, with a central search engine and user interface, - A central model independent of Z39.50, which has metadata repositories and user interface at a single place. Both models are adequate to run the EULER services, however, they have specific advantages and disadvantages. For future developments, it is planned to work on a service model that combines the advantages of both systems while eliminating the ir drawbacks.