Here's an interesting site--The Open Syllabus Project. It's an online data base that has collated books assigned in over one million college courses over the past decade.
Go to the filter "Theology and Religious Education" and you'll see that Augustine's "Confessions" is the number one book. To my surprise, several of the books I wasn't familiar with, like those by Catholic theologian Walter Kasper.
It be interesting to see how many of these books are available in Logos.
