'Himmler' was the German cover operation to provide a pretext for the 'Weiss' (i) invasion of Poland (31 August 1939).

The undertaking was centred on the so-called 'Gleiwitz incident', a stage-managed attack on the German radio station Sender Gleiwitz in Upper Silesia. This was in fact just one of several parts of 'Himmler', an undertaking designed to create the appearance of Polish aggression against Germany, and thus 'justify' Germany’s long-planned 'Weiss' (i) aggression against Poland.

The incident was organised by Alfred Naujocks under the supervision of SS-Gruppenführer Reinhard Heydrich (head of the Sicherheitspolizei) and his deputy, SS-Gruppenführer Heinrich Müller. During the night of 31 August a small group of German operatives, dressed in Polish uniforms and led by Naujocks, seized the Gleiwitz station and broadcast a message in Polish that urged the Poles living in Silesia to strike against Germans.

The object was to make the attack and the broadcast look like the work of anti-German Polish insurgents. In order to make the attack scene more convincing, therefore, the Germans brought in Franciszek Honiok, a German Silesian of known Polish sympathies, and who had been arrested on the preceding day by the Gestapo. Honiok was dressed as an insurgent Pole, killed by lethal injection, given gunshot wounds, and left dead at the scene. The appearance of the body suggested that Honiok had been killed while attacking the station, and the corpse was subsequently presented to the civil police and the press as proof of the attack. In addition to Honiok, several other convicts and/or concentration camp inmates were kept available for this purpose as 'Konserven' (canned goods).

At the same time as the Gleiwitz attack there were other incidents orchestrated by Germany along the Polish-German border, such as house burning in the 'Polish Corridor' (linking Poland with the Baltic Sea at Danzig) and a mass of broadcast misinformation. Comprising 21 incidents in all, 'Himmler' was designed 'prove' that there was a programme of Polish aggression against Germany.