College seminary focuses mainly on philosophy. Major seminary will focus on theology. The USCCB requires 30 course hours of philosophy and 12 of theology in addition to a bachelor’s degree.
The philosophical curriculum will include the study of the history of philosophy (ancient, medieval, modern, and contemporary), logic, epistemology, metaphysics, philosophy of nature, natural theology, anthropology and ethics.
The 12 semester credit hours will be in appropriate courses of undergraduate theology. These courses will study the themes of the Catechism (doctrine, liturgy and sacraments, morality, prayer) as well as Sacred Scripture.
You can’t buy the books ahead of time because each school and professor will require different textbooks.
You can read more in the USCCB’s Program of Priestly Formation.