In this paper, we formalize the digital library (DL) integration problem and propose an overall approach based on the 5S (streams, structures, spaces, scenarios, and societies) framework. We then apply that framework to integrate domainspecific (archeological) DLs, illustrating our solutions for key problems in DL integration. An integrated Archeological DL, ETANA-DL, is used as a case study to justify and evaluate our DL integration approach. More specifically, we develop a minimal metamodel for archeological DLs within the 5S theory. We implement the 5SSuite tool set to cover the process of union DL generation, including requirements gathering, conceptual modeling, rapid prototyping, and code generation. 5SSuite consists of 5SGraph, 5SGen, and SchemaMapper, each of which plays an important role in DL integration. We also propose an approach to integrated DLs based on the 5S formalism, which provides a systematic method to design and implement DL exploring services. r 2008 Elsevier B...