According to Michael Hoffman's substack:

David Irving, March 1938 - February 2024

"Mr. Irving was an English military historian of the Second World War in Britain and Europe with the distinction of having interviewed more of the principals than any other historian— from British Air Marshal Sir Arthur Harris to Traudl Junge, Hitler’s private secretary who was with Hitler up to his suicide in his Berlin bunker.

As well as the führer’s generals and politicians, Irving interviewed Hitler’s chauffeur, personal photographer, bodyguard, valet and factotums. When he asked these individuals if other historians had contacted them for interviews, almost invariably the reply he received was that they had not.

Irving’s work in British, American, German and Russian archives and in acquiring the letters and diaries of movers and shakers, including Winston Churchill’s desk diary, earned him a plaudit from Hugh-Trevor-Roper for what the latter termed Irving’s “indefatigable scholarly industry.”