If theology is the study of God, systematic theology is the subdiscipline concerned with summarizing and understanding, as a coherent system of thought, the doctrinal traditions of Christianity.
Roman Catholic systematic theology attempts to best present a synthetic understanding of the Christian faith as mediated through the Scriptures and the Catholic Tradition and as interpreted by the conciliar and papal magisterium. It focuses on theological questions about anthropology, revelation and faith, dogma and the development of doctrines, Christology and soteriology, Trinity, ecclesiology, eschatology, and a theology of religions. Sometimes the field is called doctrinal or dogmatic theology.
The subdiscipline is called systematic theology because of a contemporary focus on understanding Christian thought—dogma, doctrine, revelation, and reflection on revelation--as an organic whole, a system of propositions that define and influence each other.
From John Ford's Glossary of Theological Terms
Although the Catechism of the Catholic Church is an excellent resource for catechesis (learning the faith), it is not truly a theology text. The Catechism pulls from many theologians’ works on dogma and doctrine to present their ideas in ways understandable to the new or growing believer. Use it, but look at its footnotes--and read what the theologians had to say on the topic.
Most contemporary Church documents, including the documents of the Second Vatican Council, may be found at the Vatican’s website.
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