A great book is time-tested. People from multiple generations have had their hands on it, and have judged it to be worth passing along. It has outlived its original context, and been found useful to people in another age. This rules out recent books. Somebody might have written a truly great book (in our Socratic sense) yesterday, but we won’t know for another 50 to 100 years. If we admit Flannery O’Connor and CS Lewis to our curriculum, it’s with a little embarrassment, an admission that we’re just sentimentally attached to them, and that for all we know they might pass from usefulness before many more decades