Copac (originally an acronym of Consortium of Online Public Access Catalogues) was a union catalogue which provided free access to the merged online catalogues of many major research libraries and specialist libraries in the United Kingdom and Ireland, plus the British Library, the National Library of Scotland and the National Library of Wales. It had over 40 million records from around 90 libraries, representing a wide range of materials across all subject areas. Copac was freely available to all, and was widely used, with users mainly coming from Higher Education institutions in the United Kingdom, but also worldwide. Copac is valued by users as a research tool.