Abstract: A method and apparatus for retrieval of data relating to a plurality of levels of information comprises a store and a retrieval engine. These are arranged so that a plurality of storage areas are divided into a plurality of segments. Data relating to a given level of information for a topic is stored in a segment of one of the storage areas and data relating to at least one other level of information on the topic is stored in a corresponding segment of at least one other one of the storage areas. The retrieval engine comprising determines a selected level of information on a topic to be retrieved in response to a user request and is arranged to retrieve other levels of information on request or automatically.