Allen Packwood is in an ideal position to gauge the causes of WWII.
As director of the Churchill archive centre, at Churchill college, Cambridge, Mr Packwood looks after a wealth of material available to teachers.
"World War II is an absolutely enormous subject," he said.
The Churchill papers, consisting of letters the former prime minister wrote, drafts of his speeches and official documents, take up 2,500 boxes.
There are 600 other collections related to WWII, and similar-sized archives at the Imperial War Museum and National Army Museum.
Mr Packwood said teachers should not be put off by the volume of material showing the economic, social and military causes of the conflict. "To miss all of this out would be a cop out," he said.