Cognitive style refers to preferences for, or dominant modes of, information processing. Cognitive styles tend to be bipolar and less value-laden than ability or aptitude measures. Conceptualizations of cognitive style differ in the number of styles and the degree of metacognitive control over them which individuals are presumed to have. The Hill model, the McKenny-Keen Model, and the Cognitive-Dimensions Model are discussed. In particular, the paper describes measures and reviews research pertaining to nine cognitive dimensions identified in an earlier review by Messick: (1) field dependence-independence; (2) reflectivity-impulsivity; (3) scanning; (4) breadth of categorization; (5) conceptualizing style; (6) cognitive complexity-simplicity; (7) leveling-sharpening; (8) distractibility; and (9) tolerance for unrealistic experience. Other cognitive style definitions utilize visual-haptic, analytical-global, and verbal-visual dimensions. Research on relationships among measures is summarized, and their lack of convergence suggests that there are a multitude of cognitive styles or dimensions of cognitive style. The dimensions that seem most conceptually comprehensive and potentially independent are field dependence-independence, distractibility, tendency to use global versus analytical problem-solving strategies, and preferred medium for obtaining information (e.g., visual-haptic; verbal-visual). (LPG)