"The end for which Jesus established His Church is the salvation and sanctification of souls." Fr. Slater traces the history of Moral Theology from the time of Jesus Christ until the beginning of the twentieth century. He shows the connections between the three times period, Patristic, Scholastic and Modern and who the science of moral theology has evolved over the centuries. St. Alphonsus writes: "a single bad book will be sufficient to cause the destruction of a monastery." Pope Pius XII wrote in 1947 at the beatification of Blessed Maria Goretti: "There rises to Our lips the cry of the Saviour: 'Woe to the world because of scandals ' (Matthew 18:7). Woe to those who consciously and deliberately spread corruption-in novels, newspapers, magazines, theaters, films, in a world of immodesty " We at St. Pius X Press are calling for a crusade of good books. We want to restore 1,000 old Catholic books to the market. We ask for your assistance and prayers. This book is a photographic reprint of the original The original has been inspected and many imperfections in the existing copy have been corrected. At Saint Pius X Press our goal is to remain faithful to the original in both photographic reproductions and in textual reproductions that are reprinted. Photographic reproductions are given a page by page inspection, whereas textual reproductions are proofread to correct any errors in reproduction.