 It was during this period that he became interested in philosophy, studying it by correspondence with Gérard Granel at the Université de Toulouse-Le-Mirail.His transformation in prison is recounted in his book, "Passer à l'acte" (2003; the English translation of this work is included in the 2009 volume, "Acting Out").In 1987–88, with Catherine Counot, Stiegler commissioned an exhibition at the Centre Georges-Pompidou, entitled "Mémoires du futur