This course provides an in-depth examination of the Second Vatican Council, its historical antecedents, and its profound impacts on Catholic life and thought. Beginning with the Modernist Crisis of the late 19th century, students will explore the theological and philosophical underpinnings that set the stage for Vatican II. The course covers the preconciliar period, the history of the council, its key documents, and the sweeping postconciliar reforms initiated by subsequent Popes. Special attention will be given to the various responses from groups within the traditional Catholic movement, analyzing their positions and their broader implications for the Church. Through a combination of lectures, primary source analysis, and critical discussions, students will gain an understanding of the crisis within the Church sparked by Vatican II and how to respond to it.