 The book states that Marxism–Leninism can be successfully combated only by a "profound faith, an unlimited obedience to the Holy Father, and a thorough knowledge of the Church's doctrines"; and Caggiano thanked the "men of "La Ciudad Católica" of Argentina" for publishing the book.Along with Colonel Jean Gardes, French expert in psychological warfare, Ousset developed the new concept of "subversion".According to Horacio Verbitsky, who does not say that it was expounded in the book, this concept "conceived a protean, quintessential enemy who, rather than being defined by his actions, was seen as a force trying to subvert Christian order, natural law or the Creator's plan."