We are in the Barking Crab in Boston’s Seaport District. Nicholson Baker has just finished his lunch of Guinness, oysters and tuna. He is distraught. “In the worst case,” he says, “you would have had 15 years of the Third Reich at peace in Europe. That is an incomprehensibly bad thing, but, as long as the United States and England reopened their borders, millions of people would have survived. And I don’t care about British hon-our, I’m not interested in it. I’m interested in the people who were actually suffering at the bottom of the hierarchy in Germany – those were the Jews.”

His eyes are fixed on some distant, western point in the vicinity of Fenway Park or Cambridge. “I think even the absolute worst moment – which is allowing this idea of Adolf Hitler to be in charge of an entire sub-continent for the duration of his life, however long it was, and yet at peace – that that horrific idea would have allowed more beautiful things to survive everywhere (truth, public truth, beautiful buildings and human beings) than what actually happened.”

Baker has written a nonfiction book, Human Smoke: The Beginnings of World War II, the End of Civilization, which opens in April 1892 with Alfred Nobel musing that the explosives he manufactures may put an end to war. It ends in December 1941 with the entire world at war and the Holocaust raging in Europe.

The book is a series of very brief fragments and images that, woven together, tell a story that many will not want to hear. It is history written by a novelist, with a strong narrative drive and dramatic sense. The fragments tell multiple stories simultaneously, revealing connections between continents and time frames. The more you read, the less disjointed and more ominous it becomes.

Baker believes that the allies flung aside all possibilities of peace, that Roosevelt deliberately provoked the Japanese, and Churchill inaugurated bombing of civilian populations to provoke Hitler to respond by attacking London and, ultimately, draw America into the war. This offering up of London especially offends Baker. “There’s an England that entirely swallows up Churchill. He should be seen as a minor figure compared to the real greatness of Tennyson or Macaulay, the real people. Churchill put at risk everything that is important about the history of England – Westminster Abbey, the House of Commons, for God’s sake!”

The German leadership, he argues, may have been evil, but the allies were warmongers, handling this diseased outbreak in Europe in precisely the wrong way. Imagine, he says, a madman holding hostages in a building. Some hostages get out but are driven back in by the police. Then the police attack, setting fire to the building. The madman kills the hostages and, finally, himself. The police did everything wrong, says Baker, and so did the allies.

All of which will be, for anybody who has read Baker’s previous books, astounding stuff. He is best known as the great quirky miniaturist and eroticist of modern fiction. His first novel, The Mezzanine, took place in a lunch hour; his second, Room Temperature, lasted as long as it took for a man to feed his baby. Then there was Vox, about phone sex – Monica Lewinsky reportedly gave this one to Bill Clinton as a present – and The Fermata, one long and quite fantastically dirty story about a man who can stop time and take off women’s clothes. But he thinks – and I agree – that his best book was the nonfiction U and I, which was all about his fixation on the work and status of John Updike. On the basis of his almost deranged focus on detail – he once wrote extensively on the perversity of making drinking straws that float – critics regularly diagnose obsessive compulsive disorder.

“My wife shakes her head when they say that. I’m just a normal slob, that’s what I am. If I’m obsessive compulsive then any writer is: it’s obsessive to work through a topic and come up with a book about it. I’m within the normal range. Some people think I must be very neat or fussy, but I just want to know what happened.”

Neat, in fact, is the last thing I would accuse him of being. He is a shambling, insomniac, thickly bearded and balding 6ft 4in. Only his very slender and delicate fingers suggest the sensitivity of the man. Almost every interaction with the world is suffused with awkwardness. Our three-venue interview – at the Athenaeum Library, Borders bookshop and the Barking Crab – is littered with curious hesitancies. At the library, he is worried that we might be disturbing students; at Borders, he is briefly trapped in a revolving door with a lady whose handbag strap has got stuck; at lunch, he is flung into confusion when the waitress asks how many oysters he would like (we agree any odd number other than nine is unacceptable) and then, when they arrive, by how to eat them. Though he lives in Maine, he hasn’t eaten an oyster in 20 years; his wife, Margaret Brentano, is allergic.

And, finally, symbolically, he shares Updike’s terrible affliction – psoriasis. He rolls up his sleeves to show me his scarred arms. “I have itched and bled for so many years, it’s almost as if my brain is able to turn it off. Of all the trials one could have, it’s not really a bad problem, it’s just unsightly, and I bleed easily.” He laughs.

Born in 1957, the son of two designers, he went to music college, where he played the bassoon. “It happened in the fourth grade. I saw there were violins and then big violins and then even bigger violins, and there were drums, and then there was this machine like a Victorian steam engine elongated and turned into a musical instrument, and then out of it came the vox humana, the human voice. It’s a singing instrument.”

At 17 he was trying to compose atonal music – the orthodoxy of the age – and not getting anywhere. Then he discovered books.

“There was a whole section of the newspaper devoted to books. People took them seriously and they were excited about them. You could understand them, you could do the equivalent of tapping your feet to them, and they’ve got harmony. I found in literature something true in the same way that an A flat major chord is true, true in the way the human brain responds to sound.”

This is crucial. Critics have often called Baker a “postmodern” author. But it’s a word he doesn’t understand. In fact, he’s premodern. He says the very words “19th century” thrill him, and his prose heroes are De Quincey, Macaulay, Ruskin and Pater. He is fixated on big, rusting monuments of the industrial age, staring awestruck at an old bridge outside the Barking Crab and affectionately kicking an old, rusted gear-wheel lying on the quayside. He admits to an ambition to wander round Boston photographing all the brick buildings. His obsession with detail is an extension of this. He wants his own mental tics and the little things of life to be made, through literature, as solid as these things, to transfer them from the realm of the ephemeral to that of the semi-permanent.

“It’s like describing buttering toast,” he says in an ironic attempt to explain himself. “There’s something there that points to a bigger theme, like the fact that we’re all going to die, and these little details are nice.” He emits a large, self-deprecating laugh.

His writing career took a while to get going. He had short stories published here and there, but he had to support himself as a Wall Street broker – for a while this turned him into a 1980s neo-conservative – and as a temp, transcribing tapes around offices in Boston. All of this fed directly into his first novels, especially the transcribing, which led to the idea of stopping time, as you might stop a tape, in The Fermata.

Finally – thanks, in part, to the president’s indiscretions – Vox became a best-seller and the Baker family (he has a son and a daughter) celebrated at a dinner table littered with toy money. Baker the miniaturist had become Baker the distinguished author, though, in fact, he had already had his greatest reward. After U and I, Updike had sent him a novel with an inscription that thanked Baker for making him famous. He was delighted with the elegance of that warm and very Updikean irony.

Then, at some point, his painstaking transferring of the fleeting things of the world into literature stopped being quite enough. He discovered that libraries around the world were not only copying newspaper archives onto microfilm, they were also destroying the originals. For a man who stares in rapture at rust and brick, this was blasphemy. From the British Library, he bought 20 tonnes of bound newspapers and moved them to a warehouse near his home. With his wife, he became a curator; scholars visited. But, more to the point, Baker began to read through decades of the Chicago Tribune and New York Times. “Newspapers are so complicated, so immediate and so anchored to a particular moment. It was really exciting to be in this huge room surrounded by 20 tonnes of newspapers.”

He was reading about Hiro-shima in the NYT at about the time Iraq was being invaded. The need to overthrow Saddam was being compared to the need to overthrow Hitler. Baker was opposed to the invasion and had tried to explain why in a novel, Checkpoint, which consists of a debate with a man who wants to assassinate George Bush. It was badly reviewed, and he accepts it was a failure. So he decided to try something new. He began to create a vast body of research, from newspapers as well as primary and secondary sources, about the origins of the second world war.

“I wanted to look at the war that everyone kept referring to as a war that was necessary and good and justified, and just say, ‘Okay, let’s take a look at the beginning of it.’”

He was taking on one of the central nation-defining narratives of both Britain and America. Our joint stand against the evils of murderous racism and fascist imperialism is, in the popular imagination, a tale of unqualified good overcoming unmitigated evil. Baker, the story-teller, understands the power of this tale. “It’s very understandable. It was a war in which so many people did heroic things, and you can’t take anything away from heroism and sacrifice, and from the human emotions that spring from generous impulses. It’s just that it’s worth asking whether this massive military response to Hitler helped anybody who needed help.”

He has already suffered withering criticism in America for his conclusion: that in the late 1930s, the pacifists were right and we should have come to terms with Hitler and the Japanese. Things will be worse in Britain, I warn him, where Churchill looms large, even in the minds of the young.

“There’s no doubt Churchill was a titanic figure, a brilliant man, a great writer, a genius. But it’s a mistake to let this lead us into an acceptance of things we should feel unhappy about. We, as the good guys, have the duty to look closely at what the good guys did – more closely at what the good guys did than at what the bad guys did – because these are the people we trusted and believed in.”

I’m sure he’s wrong in his belief that, in 1939, pacifism was the better policy; and the idea that we could live with a Nazi Europe in peace is simply implausible. But he’s honourably wrong. He is a gentle, sweet man, wounded by human brutality. Perhaps, I suggest to him, as an American, he simply doesn’t understand the horror of the real possibility of national obliteration we faced in 1940, a horror Churchill soothed with his speeches telling us that, confronted with this prospect, it would be equally good to live or die. He nods. “That’s very compelling.” Then I tell him of my childhood memory of the docklands’ cranes on the Thames bowing as the barge bearing the body of Churchill passed. He stares in wonder. “Oh God, that’s so beautiful.”

His next book is a novel about a man to whom nothing much happens. Then he’ll write about the experience of writing Human Smoke. It will, I expect, be harrowing in a quite different way.

Human Smoke: The Beginnings of World War II, the End of Civilization, is published on May 6 (Simon & Schuster £20)

www.bryanappleyard.com

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