Further, he writes:
"Every age has its own outlook. It is specially good at seeing certain truths and specially liable to make certain mistakes. We all, therefore, need the books that will correct the characteristic mistakes of our own period...The only palliative is to keep the clean sea breeze of the centuries blowing through our minds, and this can only be done by reading old books. Not, of course, that there is any magic about the past. People were no cleverer then than they are now; they made as many mistakes as we. But not the same mistakes."
You can read Lewis's entire essay here.
Audio can be found here and here.
Courage and Godspeed,