Heinrich Luitpold Himmler (pronounced [ˈhaɪnʁɪç ˈluˑɪtˌpɔlt ˈhɪmlɐ] ( listen) 7 October 1900 – 23 May 1945) was Reichsführer of the Schutzstaffel (SS), a military commander, and a leading member of the Nazi Party (NSDAP). As Chief of the German Police and the Minister of the Interior from 1943, Himmler oversaw all internal and external police and security forces, including the Gestapo (Secret State Police). Serving as Reichsführer and later as Commander of the Replacement (Home) Army and General Plenipotentiary for the entire Reich's administration (Generalbevollmächtigter für die Verwaltung), Himmler was one of the most powerful men in Nazi Germany and one of the persons most directly responsible for the Holocaust.

As overseer of the concentration camps, extermination camps, and Einsatzgruppen (literally: task forces, often used as death squads operating to the rear of frontline troops to murder Jews, communists and 'untermensch' in occupied territories), Himmler coordinated the killing of some six million Jews, between 200,000 and 500,000 Roma, many prisoners of war, and possibly another three to four million Poles, as well as other groups whom the Nazis deemed unworthy to live, including people with physical and mental disabilities, Jehovah's Witnesses, members of the Confessing Church, and homosexuals. Shortly before the end of the war, he offered to surrender both Germany and himself to the Western Allies if he were spared prosecution. After being arrested by British forces on 22 May 1945, he committed suicide the following day before he could be questioned.

Katrin Himmler (born 1967 in Dinslaken) is a German author. She is the granddaughter of Ernst Himmler, who was the younger brother of Heinrich Himmler, one of the leading figures of Nazi Germany and principal architect of The Holocaust. Her book Die Brüder Himmler: Eine deutsche Familiengeschichte was published in 2007 in Germany by Fischer Taschenbuch and in English by Macmillan as The Himmler Brothers: A German Family History.

Himmler is married to an Israeli, and said that she researched and wrote the book so that her son would have a full understanding of his family's history. She told an interviewer: "When my husband and I had our son, it became clear I had to break with the family tradition of not speaking about the past. I wanted to give my son as much information as possible, so that when he starts asking questions about my family, at least I can answer him."

Himmler's book traces the lives of the three Himmler brothers (the eldest was Gebhard Himmler), the sons of a respected secondary school headmaster in Munich. Gebhard served in the German Army in World War I, but Heinrich, who at 18 was still an officer cadet when the war ended, was too young to see frontline service. Katrin Himmler speculates that it was frustration at this and envy of his brother that led Heinrich to join the extreme right-wing Freikorps in 1919. In the Freikorps he served under Ernst Röhm and was thus led into the Nazi Party.

David John Cawdell Irving (born 24 March 1938) is an English writer, best known for his denial of the Holocaust, who specialises in the military and political history of World War II, with a focus on Nazi Germany. He is the author of 30 books on the subject, including The Destruction of Dresden (1963), Hitler's War (1977), Uprising! (1981), Churchill's War (1987), and Goebbels: Mastermind of the Third Reich (1996).

His work on Nazi Germany became controversial because of his sympathy for the Third Reich, antisemitism and racism. He has associated with far right and neo-Nazi causes, famously during his student days seconding British Union of Fascists founder Oswald Mosley in a University College London debate on immigration. He has been described as "the most skillful preacher of Holocaust denial in the world today".

Irving's reputation as an historian was widely discredited after he brought an unsuccessful libel case against the American historian Deborah Lipstadt and Penguin Books. The court found that Irving was an active Holocaust denier, antisemite, and racist, who "associates with right-wing extremists who promote neo-Nazism," and that he had "for his own ideological reasons persistently and deliberately misrepresented and manipulated historical evidence."