This book presents a new theory of the relationship between vagueness, context-sensitivity, gradability, and scale structure in natural language. Heather Burnett argues that it is possible to distinguish between particular subclasses of adjectival predicatesDLrelative adjectives like tall, total adjectives like dry, partial adjectives like wet, and non-scalar adjectives like hexagonalDLon the basis of how their criteria of application vary depending on the context; how they display the characteristic properties of vague language; and what the properties of their associated orders are. It has been known for a long time that there exist empirical connections between context-sensitivity, vagueness, and scale structure; however, a formal system that expresses these connections had yet to be developed. This volume sets out a new logical system, called DelTCS, that brings together insights from the Delineation Semantics framework and from the Tolerant, Classical, Strict non-classical framework, to arrive at a full theory of gradability and scale structure in the adjectival domain. The analysis is further extended to examine vagueness and gradability associated with particular classes of determiner phrases, showing that the correspondences that exist between the major adjectival scale structure classes and subclasses of determiner phrases can also be captured within the DelTCS system.