Letters to Malcolm: Chiefly on Prayer
- Annotations and Study Guide to Letters to Malcolm (Peter Schakel)
- Quotations and Allusions in C. S. Lewis, Letters to Malcolm (Arend Smilde)
Out of the Silent Planet
Till We Have Faces
- Reason and Imagination in C. S. Lewis: A Study of Till We Have Faces (Online book by Peter Schakel)
- Till We Have Faces (Lecture by Peter Kreeft)
The Abolition of Man
