This is Derrida's most sustained work on aesthetics. Its trajectory is to explore the margins of the work of art as a seperate, unique totality. To do this, Derrida investigates how we talk about art, especially in the writings of Kant, whose discussions of the relationship between the 'work' and its 'parergon' form the heart of Derrida's text.
This is an important and rewarding book, but, be warned! It is one of the most demanding of Derrida's texts currently available in English, and it is absolutely not the best place to begin exploring the thought of this great, but challenging, thinker.