1. A search and navigation system for a set of materials, comprising: a plurality of attributes characterizing the materials; a plurality of values describing the materials, wherein each of the values has an association with at least one of the attributes and each association defines an attribute-value pair; a plurality of navigation states, wherein each navigation state corresponds to a particular expression of attribute-value pairs and to a particular subset of the materials; and a search interface, the search interface including a free-text search tool for accepting free-text queries, the search interface being adapted to generate multi-term interpretations of free-text queries, a multi-term interpretation including a conjunction of attribute-value pairs that corresponds to a navigation state,the search interface providing a display of a set of search results for a query, the set of search results including multi-term interpretations.