After occupying the Balkans early in the war, the Axis powers constantly struggled to police the region. The partisan presence was quite substantial, and while the various fractured guerrilla groups expended a great deal of energy fighting among themselves, they were still a threat to German/Italian control. The Germans and Italians were heavily engaged with the Allies across multiple fronts, so manpower was thinly spread. Therefore, much of the responsibility for combating a ruthless and in some cases highly militarized resistance contingent fell to nonmilitary police units. 

An example of such a unit is the Zollgrenzschutz (customs-border protection) of the Hauptzollamt (main customs office) Villach. Villach lies where the borders of Austria (then part of Greater Germany), Italy, and Slovenia meet. It is the gateway to the Julian Alps and during the Second World War was the frontier between Nazi Germany and the Balkans. Italian author Tommaso Chiussi has pieced together the history of the unit through painstaking original research in German, Austrian, Italian, and Slovenian archives. Included with the manuscript are more than 90 photos, most of which are previously unpublished.