Retouching, the process employed by paper conservators to replace damaged or lost areas of media, is carried out directly on the original item or on paper infills. Interventive retouching on an original surface requires the consideration of several important ethical issues such as reversibility and authenticity. The use of retouching on infills, which could be termed non-interventive, is easier to accept, as it can always be made reversible and can normally be easily identified as a later addition to the original work. The focus of this book is on interventive retouching and the question of reconstruction, including digital reconstruction and facsimile reintegration. As artworks are intended to be seen, it can be argued that aesthetics are of paramount importance. Retouching may be used as a means to preserve the legibility and composition of the image for the viewer and as such it may be considered a necessary or unnecessary evil.