Richard Meinertzhagen was a military hero, explorer, spy, friend of Israel, diarist, world renown Ornithologist and prevaricator. Unlike most people, he reveled in the lies that he told and the reactions of those he told them to. He left an 82 volume library of his 'life', much of which was wishful thinking or down right false, but like Dr.Goebbels he believed that if you tell "The Big Lie" forceful enough and long enough, people will begin to believe.
Why would a man who was respected as a world class ornithologist, get himself barred from the British Museum for stealing? Was it for the notoriety? Having re-written his diaries (in some cases many times) and destroying all the previous versions, did he want to be caught after his death? Like publicity, being remembered, whether for good or bad, is still being remembered.
Garfield, who admits the man was one of his heroes as a child, spends a lot of time trying to find back-up information to prove RMs tales. But the more his digs, the more his finds that it like digging a hole in the dessert, it buries you. When RM writes that he did so-and-so, Garfield is able to find that not only wasn't he involved, but that RM might not have even been anywhere in the area (much less on the same continent) when the event occurred.
Ian Fleming had written that RM was the archetype for "James Bond". He could not have known how right he was in basing his fictional spy on a real-life falsified spy. The sad part is, had RM just written about his real accomplishments, his story would still be one of an outstanding personality; it just wasn't outstanding enough for him.