Aquinas anticipated everything

So notes a friend who sent me this image of the cover of a dissertation from the 1950s.  (No doubt the author was using the phrase in a different sense than has now become familiar.  Any guesses as to the true subject matter?)

UPDATE: Dave Lull sends the following:

From page 1:

“Social distance may be thought of either as an attitude of mind or as those acts flowing from this mental state. An attitude of social distance is an erroneous bias unreasonably held by the individuals of one group against another group. Acts of social distance are unjust differential treatment of individuals considered to belong to a particular group. It will be the task of the following section on the psychology of social distance to explain these definitions according to Thomistic philosophy.
“Prejudice is a broader term than social distance. It is the genus of which social distance is a species. For that reason much of what is said of prejudice or prejudicial attitudes pertains to social distance. Prejudice may be defined as an attitude of mind towards persons or things producing a bias in favor of, or adverse to, such persons or things and a judgment on them before adequate knowledge of the facts has been obtained.”
See also the explanation from Brandon in the comments below.