Publisher Summary This chapter discusses the relation between stimulus analyzability and perceived dimensional structure. The combination of integral dimensions yields stimuli that are phenomenologically fused or wholistic, whereas the combination of separable dimensions yields stimuli with perceptually distinct components. Operationally, integral dimensions produce a Euclidean metric in direct distance scaling, classifications based on a distance or similarity structure in a restricted classification task, a redundancy gain in speeded classification when the dimensions are correlated, and interference in a filtering task when the dimensions are orthogonal and selective attention is required. Some dimensional combinations meet these operational criteria extremely well; value and chroma of a single Munsell chip uniformly produce results that are consistent with the operational definition of integral dimensions and, similarly, size of circle and angle of radial line are clearly separable. The evaluation of the subjective independence of dimensional combinations by the algebraic properties of the additive difference model is important in drawing the distinction between integral and separable dimensions.