In the introduction to his fine work, What We Can’t Not Know: A Guide, J. Budziszewski says that C. S. Lewis’s little book The Abolition of Man is “perhaps the greatest work on natural law in the twentieth century.” (He also adds that “most scholars of natural law have never heard of it.”)
Perhaps the most famous line is his lament of the modern educational system producing “men without chests”:
It is not excess of thought but defect of fertile and generous emotion that marks them out. Their heads are no bigger than the ordinary: it is the atrophy of the chest beneath that makes them seem so.
In rereading the book a few years ago I wished for a new edition of the book with a good introduction, outline, and notes. Well, we’ll have to keep waiting for such an edition, but in the meantime, here’s a very helpful 13-page handout on “An Introduction to and Themes from C. S. Lewis’s The Abolition of Man” by Professor David Naugle of Dallas Baptist University.
(See also his lecture “Trousered Apes, Urban Blockheads, Men Without Chests: C. S. Lewis’s Philosophy of Education in The Abolition of Man.”)