Another highlight from the collection -- the British WWII forgery depicting Hans Frank.
Hans Frank was a German lawyer and Nazi Party official who, upon the capture of Poland, became Governor-General of the Polish Generalgouvernement (the German administrative region covering occupied Poland). In this position, he was directly responsible for the atrocities committed on Polish citizens during the war, and as a result, he was tried at Nuremberg and executed after the war.
The stamp design is an imitation of the 1941 Generalgouvernement 20 Groschen Hitler Head Issue #77.
The stamps were airdropped to the Polish Resistance in January-April 1943. The Resistance mailed a small quantity of covers, each containing a propaganda leaflet, bearing the stamp and two genuine 2-Groschen stamps to various addresses in Occupied Poland.
The covers are rare (and even more rare with the original leaflet). The mint copies are less rare, but due to demand, the catalog value has risen quite a bit in the last few years -- from €500 (2001) to €3,200 (2013) for MNH.
These posts of yours are fascinating - items that I am unlikely to ever see offered, never mind having them in my collection. And your link to the propaganda issues is very interesting, that's a remarkable amount of detail to be found there.