Agreed! C.S. Lewis was a remarkable writer, and a remarkable person. And I'll take your post as a reminder that I need to go back and read his works again.
Everyone should read the Holy Scripture, then maybe read all of Augustine's anti-Pelagian writings, and then work your way to Luther's Bondage of the Will and Calvin's Institutes. a'Brekel's "A Christian's Reasonable Service" is good too, as well as any sermons by Jonathan Edwards.