The aesthetic categories of "outline" and "contour" hold central significance within aesthetic and epistemological discussions across various epochs. Particularly at the thresholds of eras, reflections on the epistemological as well as production and effect aesthetic implications of outline phenomena are articulated as a medium for theoretical differentiation in art. Based on the problem history of these categories, diagrams of a history of aesthetic thought emerge, highlighting its constants, breaks, and mechanisms of modification. The dissertation traces the history of the aesthetic concept of 'contour' through significant milestones, from ancient perception theory and traditions regarding the emergence of art, through the art theory of the Italian Renaissance and French Classicism, to the main part of the study, which focuses on the development of contour.