1. A method of information retrieval, performed on a computer system that matches text in documents against user-defined descriptions of concepts, comprising: a) identification of linguistic entities in the text of documents; b) annotation of said identified linguistic entities in a text markup language to produce linguistically annotated documents; c) identification of concepts using linguistic information, where said concepts are represented in a concept specification language and said concepts occur in one of: 1) said text of documents in which linguistic entities have been identified; or 2) said linguistically annotated documents; or 3) said stored linguistically annotated documents; d) annotation of said identified concepts in said text markup language to produce conceptually annotated documents; e) checking user-defined descriptions of concepts represented in said concept specification language; and f) retrieval by matching said user-defined descriptions of concepts against said conceptually annotated documents.