1. A computer-implemented method for retrieving information comprising: storing, by a computer system, in a data structure a plurality of attribute-value pairs associated with a collection of materials, wherein each of a plurality of values has an association with at least one of a plurality of attributes characterizing the materials; providing a user interface for entering a query to retrieve information regarding the collection of materials; displaying through the provided user interface a first set of navigation options corresponding to the stored plurality of attribute-value pairs associated with a plurality of attributes; in response to a query received at the user interface that includes a selection of at least a first attribute-value pair from the displayed first set of navigation options: displaying, by the computer system, through the user interface a representation of a first navigation state responsive to the query, the displayed of the representation of the first navigation state corresponding to a first set of attribute-value pairs and to a first particular subset of the materials, the first set of attribute-value pairs including at least the first selected attribute-value pair, the first particular subset of the materials consisting of materials in the collection of materials, each of the first particular subset of the materials is described by every attribute-value pair in the first set of attribute-value pairs; and displaying, by the computer system, through the user interface a second set of context-dependent navigation options for selecting a term corresponding to an attribute-value pair to navigate from the first navigation state to another navigation state, the displayed second set of context-dependent navigation options including an option to select a term corresponding to a second attribute that was not represented in the displayed first set of navigation options; and in response to a selection of a term corresponding to a second attribute-value pair associated with the second attribute, the selection indicates a navigation option from the displayed second set of context-dependent navigation options: displaying, by the computer system, through the user interface a representation of a second navigation state responsive to the selection of the second attribute-value pair, the displayed representation of the second navigation state corresponding to a second set of attribute-value pairs and to a second particular subset of the materials, the second particular subset of the materials consisting of those materials in the collection of materials, each of the second particular subset of the materials is described by every attribute-value pair in the second set of attribute-value pairs; and displaying, by the computer system, through the user interface a third set of navigation options for navigating from the displayed representation of the second navigation state to another navigation state, the displayed third set of navigation options including an option to de-select a term corresponding to an attribute-value pair other than the selected second attribute-value pair.