I once came across a shelf of old books that belong to the administartion of German local district (Landkreis), dating from the Napoleonic occupation until quit

I once came across a shelf of old books that belong to the administartion of German local district (Landkreis), dating from the Napoleonic occupation until quite recently. Among them were editions of laws from the time of the Third Reich. It was interesting to see where the pencil marks were: the regulations how to proof your "Aryan" decent and the implications of different degrees of "Aryanness".