This paper introduces a novel user interface that integrates search and browsing of very large category hierarchies with their associated text collections. A key component is the separate but simultaneous display of the representations of the categories and the retrieved documents.Another key component is the display of multapfe selected categories simultaneously, complete with their hierarchical context.The prototype implementation uses animation and a three-dimensional graphical workspace to accommodate the category hierarchy and to store intermediate search results.Query specification in this 3D environment is accomplished via a novel method for painting Boolean queries over a combination of category labels and free text.Examples are shown on a collection of medical text.