Book excerpt: Aesthetic Concepts is an exploration of key topics in contemporary aesthetics that arise from the seminal work of Frank Sibley (1923-1996). Sibley developed a distinctive aesthetic theory through a number of papers published between 1955 and 1995 (a selection of which, entitled Approach toAesthetics, is also published by OUP). Sibley's theory is grounded in the important and influential distinction he made between aesthetic and non-aesthetic concepts in his ground-breaking paper, 'Aesthetic Concepts'. Thirteen specially written essays by British and American philosophical aestheticians bring Sibley's insight into a contemporary framework, exploring the ways his ideas give rise to important new discussion about issues in aesthetics that greatly interested him. These include: the differences andrelationships between aesthetic concepts and other types of concepts, aesthetic realism and objectivity, methods of aesthetic evaluation in practice and in theory, the boundaries of aesthetics, and aesthetics of nature versus aesthetics of art. This collection will be of interest to scholars inphilosophy, art theory, and art criticism.