In my first two years of reading the same books that I had read as a student with Erskine, but now reading them again in order to collaborate with Mark Van Doren to discuss them with our students, my eyes were opened to the fact that I had not understood them very well, if at all, on my first reading. In the next five or six years, that discovery was repeated again and again, as I learned more each time I reread the same books I had read before. Now at the end of my life, still rereading the great books that I started reading seventy years ago, I can summarize this whole process by repeating two insights mentioned before in this book: (1) the great books are the books that are inexhaustibly rereadable for both intellectual pleasure and profit: (2) understanding the ideas to be found in the great books develops slowly in the course of one’s whole life, bearing its best fruits in one’s mature years after fifty or sixty.