The UK Data Archive (UKDA) is a resource centre that acquires, disseminates, preserves, and promotes the largest collection of digital data in the social sciences and humanities in the United Kingdom. Its primary aim is to support secondary use of quantitative and qualitative data for research and learning. The UKDA also houses two specialist units: the History Data Service (HDS) and Qualidata - Qualitative Data Service, and provides access to international data through cooperative agreements and memberships with archives around the world. (self-description). One of the most important features is the access to the Search Catalogue.