This introduction presents an overview of key concepts covered in the subsequent chapters of this book. The book provides a historical sketch of Macau Catholicism and its cultural–political profile. It examines the ways in which the so-called "12.3 Incident" in 1967 led to the political concession of the colonial government toward the communist regime in mainland China, and thereby the dwindling authority of the Catholic Church. A conservative culture was formed under a corporatist sociopolitical arrangement. The book reviews the Second Vatican Council, which happened to coincide with the Chinese Cultural Revolution and paved the way for the problematic implementation of Catholic social teaching in the Macau Diocese. With reference to the sociological discourse on secularization, it outlines the decline of Church authority and influences on the laity and also the general public. The book discusses some suggestions made by Catholics on the directions and prospects of Church reform.