This book would not have been possible without luck, that is, encounters—encounters with books, books’ encounters with one another, but also encounters with people—that have sparked or strengthened my philosophical work. To the first among them I owe neither the contents of the ideas here defended nor my philosophical views, nor even the tradition in which they are inscribed—he is, however, one of the people to whom I owe the most philosophically: I had the good fortune to have Jean-Luc Marion as a teacher, and neither the distance between our ways of thinking nor now the distance in time has softened the shock of this encounter. I thank you, here, finally. More recently, I also had the good fortune to encounter Michel Malherbe, who has directly contributed to the development of this book with his attentive reading, perceptive remarks, and decisive suggestions. Bernard Bourgeois benevolently guided and later accompanied all my research. Jean Gayon and Heinz Wismann have, last, given me considerable support and encouragement—I thank you both four times. Finally, I thank everyone who has helped me philosophically through their writing and their conversation: Claude Parthenay, Bertrand Rougé, Fosca Mariani, Denis Thouard, Jean-Claude Gens, Michèle Cohen-Halimi, as well as André Charrak, Sandra Laugier, Jocelyn Benoist, Christiane Chauviré, Jacques English, Anastasios Brenner, Fabien Capeillères, Félix Duportail, Olivier Imbert, Marie-Pierre Gaviano, Aline Alterman, Ives Radrizzani, Christian Berner, Chantal Jacquet, Jeanne Salem, Christian Bonnet, André Stanguennec, Marie-Dominique Popelard, and finally, Daniel Arasse, to whose memory this book is dedicated.