As the XIXth Century began its last decade, several Spanish novelists of the 'Generacion del 68', displeased with the technical and ideological limitations imposed by the experimental method advocated by naturalism, introduced new ways of exploring human reality in its totality. While they still borrowed many of the techniques introduced by naturalism, these novelists searched for new ways to express those individual and social realities which lay beyond the realm of the senses and of deduction (reason). Influenced also by the growing spiritualism, characteristic of the fin de siecle mentality, these authors explored and interpreted in their novels the religious sentiment of their society. In particular they examined the question of faith, its interpretation and its concrete effects on the life of society This study examines eleven novels of Palacio Valdes, Pardo Bazan, Luis Coloma, Leopoldo Alas and Perez Galdos which, from 1890 to 1899, deal with faith and unbelief, either as the basic conflict, or as the ideology which permeates it. After an overview on faith in general, faith in the Judaeo-Christian tradition, its development in the Church and its philosophical and theological interpretations in the XIXth century, each of the novels is first presented and then its particular interpretation is compared to the theology and official pronouncements of the Catholic Church, from Vatican I and Pope Leo XIII The study illustrates that these Spanish novelists, genuinely preoccupied with the state of society, presented their views on faith according to their own orthodox and/or heterodox convictions. Each denounced abuses and suggested ways in which religious and non-religious faith can be an asset in the restoration of society's traditional values. Each offered a new vision to society at the threshold of the XXth Century