Digital Libraries (DLs) are among the most complex kinds of information systems, due in part to their intrinsic multi-disciplinary nature. Nowadays DLs are built within monolithic, tightly integrated, and generally inflexible systems- or by assembling disparate components together in an ad-hoc way, with resulting problems in interoperability and adaptability. More importantly, conceptual modeling, requirements analysis, and software engineering approaches are rarely supported, making it extremely difficult to tailor DL content and behavior to the interests, needs, and preferences of particular communities. In this paper, we address these problems. In particular, we present 5SL, a declarative language for specifying and generating domain-specific digital libraries. 5L is based on the 5S formal theory for digital libraries and enables high-level specification of DLs in five complementary dimensions, including: the kinds of multimedia information the DL supports (Stream Model); how that information is structured and organized (Structural Model); different logical and presentational properties and operations of DL components (Spatial Model); the behavior of the DL (Scenario Model); and the different societies of actors and managers of services that act together to carry out the DL behavior (Societal Model). The practical feasibility of the approach is demonstrated by the presentation of a 5SL digital library generator for the MARIAN digital library system.