'Aesthetics' as a philosophical sub-discipline emerged in the mid-18th century when human sensory perceptions and art began to be viewed in a new way that has no precedent in the philosophical tradition: as something governed by its own, reason-analogous kind of legality, which cannot be equated with the conceptually and propositionally structured laws of reason and understanding of discursive rationality. Analyzing this self-lawfulness of sensory perception and art and highlighting its relevance for human world orientation is the program that aesthetics has since committed itself to. The book first introduces fundamental figures of philosophical aesthetics by Baumgarten, Kant, and Hegel, and then outlines positions of aesthetics in the age of modern art, including those of Fiedler, Heidegger, Adorno, and Witt.