Geosimulation has recently emerged at the intersection of Geographic Information Science, Complex Systems Theory and Computer Science. Geosimulation aims at understanding the dynamics of complex human-driven spatial systems through the use of spatially explicit computer simulation. The approaches and tools for validating Geosimulation models are especially important for understanding their complex and spatially heterogeneous outcomes. The Ebook presents the recent conceptual and methodological advances achieved in the field. It should be very useful for scientists and graduate students working in the fields of Complex Systems Modelling, Geocomputation, Science, Geography, Regional Science, Computer Science, Artificial Intelligence, Environment Simulation and Modeling, and Environmental Engineering.