MACS aims to provide multilingual subject access to library catalogues. MACS enables users to simultaneously search the catalogues of the project's partner libraries in the language of their choice (English, French, German). The partners are: the Swiss National Library (SNL), project leader, the Bibliothèque nationale de France (BnF), The British Library (BL) and Die Deutsche Bibliothek (DDB). The project is running under the auspices of the Conference of European National Librarians (CENL). This multilingual search is made possible thanks to the equivalence links created between the three indexing languages used in these libraries: SWD (for German), RAMEAU (for French) and LCSH (for English).