Dissertation zur Erlangung eines akademischen Grades eines Doktors der Philosophie der Philosophischen Fakulta?t der Universita?t des Saarlandes; Table of contents : 1. Information, Classification and Automation; 1.1 Library Classification and Automation; 1.2 Patent Information and Automation; 2. Patent Classification and Databank; 2.1 International Patent Classification; 2.2 Patent Databank - PATDPA; 3. Classification of Patent Documents; 3.1 Structure of a Patent Document; 3.2 The Purposes and Rules of Classification; 3.3 The Current Process of Classification in the German Patent Office; 3.4 Suggestions for an Automated System; 4. Directories of Patent Descriptors and Index Terms; 4.1 Directory of Alphabetically Ordered Patent Descriptors and Index Terms; 4.2 Directory of Class Number-ordered Patent Descriptors and Index Terms; 5. Indexing Principles and Techniques; 5.1 Indexing Principles; 5.2 Indexing Languages; 5.3 Indexing Systems; 5.4 Keyword Indexing; 6. An Automated System for Patent Classification; 6.1 Automated Indexing and Text Analysis (KWIT and KWOT); 6.2 Occurance Analysis and Weighting; 6.3 Selecting the Class Subject; 6.4 Assigning the Appropriate Class Number; 6.5 Completing and Updating the Directories; 6.6 Improving and Correcting Already Classified Patent Documents; 7. Classification and Automated Information Retrieval; 7.1 Classification Systems and Class Number Search in Databanks; 7.2 Classification Systems and Subject Search in Databanks; 8. Classification and Thesaurus Construction; 8.1 Thesaurus Construction; 8.2 Automated Pseudothesaurus Construction for German Patent Office; 9. Summary;.