Perception, action, cognition, and emotion can now be mapped in the brain by a growing family of techniques. Positron emission tomography, functional magnetic resonance imaging, event-related electrical potentials, event-related magnetic fields, and other non-invasive imaging techniques are rapidly evolving and providing an increasingly rich literature on the functional organization of the human brain. Although no two techniques map identical physiological processes or physical parameters, replications of functionally specific maps by different techniques indicate sufficient common ground for multimodality integration. The process of integration is multi-tiered. Recent advances in integration range from simple image fusion, to model-based synthetic analyses, to collective databases for neural-system modeling. Spatially, temporally, physiologically, and cognitively accurate computational models of the neural systems of human behavior are the ultimate objective of functional brain mapping. This objective will be reached only through integrating the diversity of modern brain-mapping methods.