Abstract: In information retrieval (IR) systems with high-speed access, especially to search engines applied to the Internet and/or corporate intranet domains for retrieving accessible documents automatic text categorization techniques are used to support the presentation of search query results within high-speed network environments. An integrated, automatic and open information retrieval system (100) comprises an hybrid method based on linguistic and mathematical approaches for an automatic text categorization. It solves the problems of conventional systems by combining an automatic content recognition technique with a self-learning hierarchical scheme of indexed categories. In response to a word submitted by a requester, said system (100) retrieves documents containing that word, analyzes the documents to determine their word-pair patterns, matches the document patterns to database patterns that are related to topics, and thereby assigns topics to each document.