"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...