For decades he relentlessly searched for and found diaries of the main figures, pried loose official documents, tracked down witnesses, searched the war archives of many countries, all of which is the material of his extraordinary histories.

The facts differed from the official narratives.  Jews took umbrage and ruined him financially, forcing his publisher to destroy their printings of his histories, which were best-sellers praised by other historians, and by bringing corrupt law suits against which he had to defend, which exhausted his financial resources and left him penniless and homeless.  

He managed to keep going with proceeds from his well-attended lectures whose locations had to be kept secret to prevent Jews from having thugs break up the gatherings.  Eventually  Jews were able to get some governments to ban him from the country in order to block his lectures. Invited to speak in Austria, he was falsely arrested and imprisoned. The stress of his life has resulted in a stroke that has disabled him.

You might imagine from my account that Irving wrote against Jews.  But that is not the case. He documented the slaughter of several hundred thousand Jews by German political functionaries in conquered parts of Russia.  He got in trouble with the Jews because he reported that his 50-year search of the world's war archives, including the Soviet and Israeli archives, failed to turn up a single document supporting the existence of an organized holocaust. He offered a monetary award to anyone who could help him find evidence of an organized holocaust.  None did. 

Irving makes it clear that Jews suffered persecution under the Nazis.  Hitler's position, stated repeatedly by Hitler was that the "Jewish question" would be settled after the war.  Initially Hitler's plan was to settle the Jews in Madagascar. After his initial victories against the Soviet Union, he talked of sending the Jews to their Bolshevik friends in the rump part of Russia that he intended to leave to Stalin.