MetaCrystal enables users to visualize and control the degree of overlap between the results returned by different search engines. Several linked overview tools support rapid exploration, facilitate complex filtering operations and guide users toward relevant information. MetaCrystal addresses the problem of the effective fusion of different search results by helping users to visually combine and filter the top results returned by the different engines. Users can apply weights to the search engines to create their own ranking functions. They can control the degree of overlap by modifying the URL directory depth used to match documents or by changing the number of top documents being compared. Categories and Subject Descriptors H.3.3 [Information Storage and Retrieval] Information Search and Retrieval - information filtering. H.5.2 [Information Interfaces and Presentation (e.g., HCI)] User Interfaces - graphical user interfaces (GUI). General Terms: Design