This study takes George Lakoff's dictum seriously that arguments about conclusions will be pointless unless there is agreement on the premises. Subscribing to the view that linguistic categorization is necessarily theory-driven, it reconstructs and assesses, on the basis of domain-independent parameters derived from General Systems Theory and Leonard Talmy's Overlapping Systems Model of Cognitive Organization, hegemonic western conceptualizations of modality. Arguing against such propositional models of modality, the book outlines, modifies, and extends conceptualizations from a Cognitive Linguistics point of view, grounding modality especially on Talmy's Imaging System of Force Dynamics. The authors conceive of modality as an experientially and perceptually motivated radial category of Image Schemata, ultimately challenging the categorial status of modality as a cognitively motivated category.