Mediaeval Philosophy: Illustrated from the System of Thomas Aquinas / Maurice De Wulf -- Cambridge, Mass.: Harvard University Press, 1922.

De Wulf's Mediaeval Philosohy is a short readable summary of a many of the central ideas in Thomas Aquinas's philosophy. Topics include, metaphysics, theology, ethics, and law. I was surprised to learn tha Aquinas held a rather robust view of the individual and human rights. Consequently, he seems much more modern than I had previously thought.