All translations are mine unless otherwise indicated. I have tried to remain faithful to the meaning and different tones of documents written by authors from a wide range of disciplines and historical periods, while rendering them in an English that is as natural and readable as possible. In the text, the first time titles of works and institutions are mentioned, they will be followed by a translation in parentheses, unless their sense can easily be deduced from English cognates. All subsequent references will use the original French. The one exception to this is the section on Odilon Redon in chapter 6, where, to comply with the practices in art history and avoid very cumbersome constructions, I have used only the English versions of his titles.