178 Chapter VII Discovering Spatio-Textual Association Rules in Document Images Donato Malerba Università degli Studi di Bari Margherita Berardi Università degli Studi di Bari Michelangelo Ceci Università degli Studi di Bari Copyright © 2008, IGI Global, distributing in print or electronic forms without written permission of IGI Global is prohibited. AbstrAct This chapter introduces a data mining method for the discovery of association rules from images of scanned paper documents. It argues that a document image is a multi-modal unit of analysis whose semantics is deduced from a combination of both the textual content and the layout structure and the logical structure. Therefore, it proposes a method where both the spatial information derived from a complex document image analysis process (layout analysis), and the information extracted from the logical structure of the document (document image classifcation and understanding) and the textual information extracted by means of an OCR, are simultaneously considered to generate interesting pat- terns. The proposed method is based on an inductive logic programming approach, which is argued to be the most appropriate to analyze data available in more than one modality. It contributes to show a possible evolution of the unimodal knowledge discovery scheme, according to which different types of data describing the units of analysis are dealt with through the application of some preprocessing technique that transform them into a single double entry tabular data.