'I suppose it was a deep fear of ignorance - both of the big events of the past and the world as it is.'
Professor Frank Dikotter - chair of humanities at University of Hong Kong, author of nine books, speaker of six languages, renowned historian and all-round likeable guy - has been wrestling to explain what drew him to his calling.
Ironically, the feted prober of the past finds it difficult to explain his own personal history. 'What inspires people to make the choices they make?' he wonders. 'I very honestly don't know.'
Nevertheless, one episode stands out. 'I was always a reader,' he explains, 'and I remember very distinctly being a young boy of about 12 or 13 and happening upon some books about the Holocaust. Discovering this through books on my own, it came as an extraordinary shock to realise that Europe, including my home of Holland, had been involved in those unimaginable atrocities while my own father was still a child.
'It struck me that tremendously huge things may have happened in the past. And to be blithely ignorant of them? I found that a very difficult thought to live with.'
Several decades later, Dikotter is confronting the wider reading world with its own ignorance of the whitewashed horrors of history. His latest book, Mao's Great Famine, is an unprecedented account of Mao Zedong's ultimate culpability for a disaster that resulted in the deaths of an estimated 45 million Chinese - from party officials, to counter-revolutionaries to scores upon scores of rural farmers.
Unlike few previous efforts in this area, almost all of Dikotter's book is based on primary sources that he uncovered during years of intrepid research in regional mainland archives during the brief period of goodwill before the 2008 Beijing Olympics, when restrictions were temporarily relaxed. The book won the 2011 Samuel Johnson Prize - Britain's most prestigious award for non-fiction writing - and was summarily banned on the mainland.
Dikotter was born in Holland, schooled in Switzerland and later attracted to the Soviet Union by a love of Dostoyevsky and the allure of the unknown. 'The cold war was still going strong at that time [the early 1980s],' he explains. 'I wanted to know what it was actually like on the other side.'
As a scholarship history student, he spent a summer in Leningrad, but 'in the end, I concluded that Russians aren't all that different from Europeans. Then a teacher suggested that I could easily get another scholarship to China, because no one else wanted to go'.
Dikotter passed the next two years studying and adventuring around China ('I spent months on the road. I saw a sky burial in Tibet before it all closed down. I went everywhere.'), and later returned to Beijing during his doctoral studies in 1988 and 1989, where he witnessed the tanks rolling into Tiananmen Square during one of his evening bike rides, which hastened him to catch one of the last trains to Guangzhou before the violence erupted.
Two major themes characterise the work Dikotter went on to produce as a prolific historian throughout the 1980s and 1990s: the pursuit of new, solid sources and fresh, morally consistent interpretations. His first eight books focused on the pre-1949 Republican period, as mainland libraries and provincial archives were then just beginning to reopen to researchers working on the era.
'I was in there like a ferret,' he says. 'And I saw the whole richness of the period - people moving in and out of the country; free circulation of thought, of goods, of people, of capital. It's a very interesting period, which, of course, has been much maligned by communist historiography.'
The conclusions Dikotter draws from his research often run counter to historical orthodoxy. His most controversial pre-1949 book, perhaps, is Narcotic Culture (2004), which argues that opium is a relatively benign substance and reinterprets the opium wars in light of an anti-prohibitionist position.
'There is large corpus of work by historians who adopt an anti-prohibitionist stance,' he says. 'But nobody had done it in the China field. And it seems to me, you have to be consistent. You cannot be a sinologist and say, on the one hand, I don't like Bush's war on drugs and I think it makes the situation worse; and then go and write about the opium wars and how the drug enslaved the nation.'
Dikotter's eventual turn to the communist era with Mao's Great Famine was a product of both opportunity and choice. During his pre-communist research in various provincial archives, he began to stumble upon declassified materials detailing the horrors inflicted on mainland farmers in the years before the Great Leap Forward.
At the same time he was motivated by a more personal sense of urgency: 'There's a point when you wonder how you can be a professional historian of modern China and not talk about the horrors that happened after 1949. I mean, should we all somehow tiptoe around this period? Should we all look away when there's a massive black hole that swallowed the lives of tens of millions of people? And write about 'representations of masculinity in People's Daily'? What kind of life is that?'
Mao's Great Famine has won Dikotter more praise and attention than his previous eight books combined, but he's quick to shrug off the fanfare and more interested in making sure people read it. 'Most authors want as wide a readership as possible for all their books,' he says. 'I wouldn't say that about my other eight, but I really mean it with this one. The topic is too important to be left to historians alone.'
Later this month the first Chinese translation of Mao's Great Famine will be released by New Century Press. Dikotter has no doubt it will be pirated, digitised and smuggled into the mainland - 'And so be it; the more people who read it the better.'
He has also begun work on a prequel, The Tragedy of Liberation, which will be based on additional archival material gathered during his research excursions into the provinces.