One of the attractions of leaflet collecting and research is that much remains to be discovered. Previously unreported leaflets often come to light. During WWII, for example, some leaflets were produced in the field by mobile printing presses and few, if any, records were kept. Only the leaflets themselves remain to tell the tale. The full facts about leaflet operations in the recent Persian Gulf War are still not known.
Some leaflets are well documented and often illustrated in the literature.
Others are obscure and need researching to establish their origin and purpose. Some turn up frequently while others are exceedingly rare. Some of the WWII leaflets which were printed in England and dropped by the RAF in huge quantities over Germany and the occupied countries over a span of many months have survived in quantity. On the other hand, leaflets disseminated by V1 rocket are exceedingly rare, primarily because they were produced in small numbers and sometimes did not survive the flight and explosion. In England the VI leaflets were quickly gathered and confiscated by the authorities before the public could find them.