Art restoration is examined in terms of the different contexts in which restoration operates. The various definitions of restoration are discussed with reference to specific examples from the field of the fine arts. The paper discusses four relevant questions relating to restoration: (1) Why would an earlier state be preferable? (2) How would we know what an earlier state is? (3) What is it about the earlier state that we want to valorize? (4) How do our ideas concerning restoration and originals relate to questions of the artist's intention? Both art connoisseurship and scientific connoisseurship may be important evaluative components in reaching a conclusion regarding the legitimacy of restoration and its impact on the works of art it purports to represent or present in an altered state. The different philosophical modes of thought that impact the ontological and aesthetic arguments as to how restoration is to be regarded are discussed in the context of particular examples of works of art that have undergone restoration, derestoration or re-restoration and that illuminate some of the problems involved.