According to the Oxford English Dictionary, dictionary can be either a book dealing with the individual words of language... or a repository of knowledge, convenient for consultation. An effective dictionary database must serve both roles simultaneously; that is, it must be capable of answering precise questions about the written dictionary text as well as the language described by that text. An effective representation for the OED has been based on the recent text structuring technique known as 'descriptive markup', which introduces tags into text stream. Thus, dictionary components are explicitly identified and delimited, so that, for example, an entry is marked by ... , an etymology by ... , usage label by ... , and cited work by ... . The most visibly successful aspect of our research is embodied in the flexible and efficient search and display software. LECTOR is general-purpose browser that takes as input stream of tagged text and formats it to the screen using typography to illustrate its structure. It uses specially-designed formatting, or display-specification, language to accomplish this, through which the choice of typographical strategies is user-selectable. As complementary software component, efficient retrieval is provided by the PAT text search engine. Each entry in the search index designates 'semi-infinite' string that starts at critical point in the text (e.g. at word start) and continues uninterruptedly to the end of the text. Text regions (e.g. those representing individual dictionary components) can be specified to limit the scope of material being searched or displayed. Used together, PAT and LECTOR form powerful query facility for text databases. Examples drawn from our experiences with researchers and casual visitors illustrate the application of these tools to exploring the OED.