Among his books, "H. P." tells the inner story of Henri Paul, the driver involved in the Death of Diana, Princess of Wales; "Porte senza porta" (expanded as "Il libro dei maestri", aka "the book of teachers" meaning in several and various disciplines) is a collection of personal meetings and some conversations which includes Bruno Hussar, Taizan Maezumi, Bruno Munari, Terry Riley, Steve Paxton, Alessandro Fersen, Daniel de Montmollin, Emmanuel Levinas, Luigi Ghirri, Elisabeth Bing, Raimon Panikkar, Mary Catherine Bateson, Frédéric de Towarnicki, and others. In 2004, he continued the meetings in a radio programme by Rai Radio 3, including Aldo Gargani, Alejandro Jodorowsky, Giulia Niccolai, etc.