What is "surnaturel"

Surnaturel is a book written by the Roman-Catholic theologian Henri de Lubac. It stands among his most famous and controversial works.

In this book he traces the historical meaning of the word 'supernatural' and notes a shift in implication. Up to the High Middle Ages, the essential contrast was drawn between 'natural' and 'moral'. After that, the contrast was seen between 'natural and supernatural'. De Lubac is trying here to establish the correct understanding of Aquinas on this subject.