1970s, Jäckel was a leading critic of the British author David Irving and his book Hitler’s War, which argued that Hitler was unaware of the Holocaust. Jäckel, in turn, wrote a series of newspaper articles that was later turned into the book David Irving's Hitler : A Faulty History Dissected. It attacked Irving and maintained that Hitler was very much aware of and approved of the Holocaust. Jäckel attacked Irving for claiming that an entry in Heinrich Himmler's notebook saying "Jewish transport from Berlin, not to be liquidated", on 30 November 1941 proved that Hitler did not want to see the Holocaust happen. Jäckel maintained that the order referred only to that train and argued that if Hitler had ordered the people on that train to be spared, it must stand to reason that he was aware of the Holocaust. Jäckel went on to argue that because the "Final Solution" was secret, it is not surprising that Hitler's servants who were ignorant of the Holocaust, and anyhow, five of Hitler's servants interviewed by Irving later claimed that they believed that Hitler was aware of the Holocaust. Jäckel argued that on the basis of Hitler's statements in Mein Kampf, the Führer was always committed to genocide of the Jews and that because Hitler later attempted to execute the foreign policy that he outlined in Mein Kampf, it is a reasonable assumption that Hitler was always committed to genocide. As a sign of Hitler's intentions, Jäckel used Hitler's tendency to involve himself in minutiae to argue that it is inconceivable that Hitler was unaware of the Holocaust. Jäckel used Hitler's "Prophecy Speech" of January 30, 1939 in which Hitler declared: I shall once again be your prophet: if international Jewry with its financial power in and outside of Europe should manage once more to draw the peoples of the world into world war, then the result will not be the Bolshevization of the world, and thus the victory of Jewry, but rather the total destruction of the Jewish race in Europe Likewise, Jäckel used Himmler's Posen speeches of 1943 and certain other statements on his part in 1944 referring to an "order" from an unnamed higher authority as proof that Hitler had ordered the Holocaust. In the same way, Jäckel noted Hitler's order of 13 March 1941 for the Einsatzgruppen to be re-established for Operation Barbarossa as proof of the Führer's involvement