Summa Theologica of St. Thomas Aquinas, 5 Vols.

Creating a summary of all human knowledge may not be the sort of undertaking we begin in the twenty-first century, but there is still room on our bookshelves for a classic--Summa Theologica, one of the world's oldest and greatest masterpieces. St. Thomas Aquinas has much to teach us--most especially how to confront the classic questions that are still with us after centuries of thought.