Book excerpt: Advanced Geographic Information Systems is a component of Encyclopedia of Earth and Atmospheric Sciences in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty one Encyclopedias. The content of the Theme on Advanced Geographic Information Systems is organized with state-oc-the-art presentations covering the following aspects of the subject: Spatio-Temporal Information Systems; Interacting with GIS - From Paper Cartography to Virtual Environments; Spatial Data Management: Topic Overview; Introduction to Spatial Decision Support Systems; GIS Interoperability, from Problems to Solutions. These volumes are aimed at the following five major target audiences: University and College students Educators, Professional practitioners, Research personnel and Policy analysts, managers, and decision makers and NGOs.