Desktop search is a new application area for information retrieval technologies, focused on searching in the local information sources on a user?s PC. These applications typically operate as local search engines and consequently exhibit all problems associated with full-text search. AutoFocus is a new desktop search application, focused on offering semantically rich interaction and serendipitous exploration instead, through the use of the Cluster Map information visualization technique combined with explicit metadata navigation. We discuss AutoFocus? user interface and Semantic Web-based architecture and report on its applicability and usability based on preliminary user feedback.