Francesc Torralba, Professor at the Universitat Ramon Llull, explores the suspicions sustained by Marx, Nietzsche and Freud, whom Paul Ricoeur identifies as the ?masters of suspicion?. Torralba says, ?Philosophy is a curious activity, not a tonic, because its goal is to make one think. These three great philosophers make us think by posing substantive questions that nobody, not even a Christian, can avoid.? In this essay, the questions of these three thinkers are analyzed with the intent of disclosing the degree of truth that each one holds. The book is complemented with counterpoints from Norbert Bilbeny, Francisco Fernández Buey and Andrés Sánchez Pascual.