Gene Sharp is not a typical pacifist. “When I used to lecture, I would always get complaints from the pacifists,” says the academic, who turns 85 this month. “They would say I wasn’t pure. They said that what I was proposing was ‘still conflict’.” Military people often understood him better. A retired US army colonel, Robert Helvey, heard Sharp lecture 20 years ago and persuaded him to visit Burma, where rebels asked Sharp to give them advice.

He wrote a pamphlet. “I didn’t know Burma well,” he recalls. “So I had to write generically: if a movement wanted to bring a dictatorship to an end, how would they do it?” That pamphlet, From Dictatorship to Democracy (1993), contained the idea for which Sharp is now known all over the world – that power is held only by the consent of the people over whom it is exercised, and that consent can be withdrawn. All regimes depend on certain pillars of support and, with a proper strategy, resisters can remove those pillars non-violently.

The book was originally published in English and Burmese. “And I thought that was it,” Sharp says. But it went on display in a bookshop in Bangkok. From there, nobody knows exactly how it spread. But it did – everywhere. “I’m still amazed. It didn’t spread because of propaganda or some sales pitch but because people found it usable, and important.”

“I had no idea how useful it would be,” confirms Srdja Popovic, a leader of Otpor, the movement that toppled Slobodan Milosevic in Serbia in 2000. Others have described the effect of reading Sharp’s work as “mind-blowing”, because it showed that what had seemed impossible might not be impossible after all.

For nearly 20 years, From Dictatorship to Democracy circulated clandestinely in as many as 40 countries. It was being printed in Moscow when the FSB (the successor to the KGB) raided the printer. It later went on sale at two independent Russian bookshops – both of which, remarkably, soon caught fire.

The British film-maker Ruaridh Arrow first heard about Sharp while covering Ukraine’s Orange Revolution. He decided to find out more, and the result of his research was a film, How to Start a Revolution, which has been shown in more than 22 countries and became an underground hit with the Occupy movement.

Now Sharp’s teachings are winning interest from the mainstream, too. From Dictatorship to Democracy finally had its official publication in the UK. The Archbishop of Canterbury invited Sharp to meet bishops from around the world. And the All-Party Parliamentary Group on Conflict Issues asked him to address MPs, peers and senior civil servants at the House of Commons. The room was packed – thanks to a crowd of Occupy activists – and he received a standing ovation. He has been nominated for the Nobel Peace Prize, and early last month in the Swedish Parliament he was presented with the so-called Alternative Nobel, the Right Livelihood Award.

After a lifetime of lonely academic toil, Sharp is suddenly finding that people all over the world are ready to hear his theory of power – and how to seize it. “This is a very strange experience,” he says. But is the acclaim overblown? The Occupy movement has largely fizzled out and the Arab spring has not been quite the success that people hoped it would be. Is he worried that his reputation will fall again? “I don’t give a damn about my reputation. The point is that bringing down one regime does not produce political nirvana. You still have tough times ahead. I have always been very clear about that.

“But people used to say non-violence can’t work. After Tunisia and Egypt, people can no longer deny that non-violent regime change is possible. The old theory of a ‘just war’ is that there must be no viable alternative. I think that’s false now. It’s no longer a theological question – it’s an empirical question.” He quotes Kenneth Boulding: “ ‘That which is, is possible.’ The breakthrough has happened.”

In person, Sharp is frail. We meet on a cold winter morning at a hotel in Westminster. We inspect a military memorial overlooked by one of the windows. He walks slowly, using a stick, and speaks quietly; talking to him, I find it necessary to lean forward to catch what he is saying.

Since 2004 he has run his Albert Einstein Institution (AEI) out of two rooms at his home in Boston near Logan Airport. His desk is piled deep with papers and the rest of the office is cluttered, too. The lack of space is a problem. “You can’t imagine the number of things I can’t find now,” he says. “I can’t find my thesaurus, or The Oxford English Dictionary. I don’t know where my copy of Aristotle’s Politics is . . . They’re in boxes; they’ve been in boxes since we moved here years ago. I miss them all the time. We have maybe 20 or 30 boxes like that. I can’t look through them, because it takes me away from doing something more important.”

It is a modest arrangement that gives the lie to the charge, repeated not infrequently by regimes in Venezuela, Iran and elsewhere, that the AEI is a well-funded front for the CIA. The institute took its name from Einstein because, as a 25-year-old conscientious objector at the time of the Korean war, Sharp opposed the draft using civil disobedience tactics, and Einstein supported him. Sharp was living in New York and writing a book about the Mahatma when he learned that Einstein, too, admired Gandhi. “I wrote to him in Princeton and said I was about to go to jail for resisting conscription and – oh, by the way, I’ve written this book.” Einstein wrote a foreword to it.

In 1953, Sharp was sentenced to two years in prison for draft-dodging. His parents, a pastor and a schoolteacher, were understandably upset. “They tried to get me to be more reasonable by applying to be a recognised conscientious objector, but I was objecting to military conscription itself.” They visited him only once in jail. Much later, after his mother died, Sharp learned that her first great love had been killed in the First World War in France – so she had been a little more understanding about his opposition to military service than his father. “But he came round, too, eventually.”

On his release, Sharp worked as the personal secretary to A J Muste, described by Time magazine as America’s number-one pacifist, then as a typist on Wall Street, and continued his analysis of Gandhi. The motive, one should note, was not sentimental. “I don’t admire Gandhi because he is ‘nice’. He was no fool. He has quotations about power and the need to struggle that, if you read them out of context, could have come from Mao Tse-tung. He was a tough cookie.”

As Muste’s secretary, Sharp had put up a visitor from a British newspaper, Peace News, who recommended him for a job. So he moved to London. Based in King’s Cross, Peace News had a weekly circulation of about 14,000. Sharp reported on demonstrations and Ministry of Defence press conferences. He soon secured an opportunity to study at Oxford for a DPhil. (He already had a BA and an MA from Ohio State University.) And by this time he had developed a general theory of non-violent struggle, based largely on Gandhi’s insights and classical political theorists such as Thomas Hobbes. His supervisor at All Souls College, John Plamenatz, was a philo sopher and a wartime member of the Yugoslav government-in-exile. Plamenatz advised Sharp not to focus exclusively on theory but to consider anecdotal evidence from actual dictatorships and revolutions.

So, living in a shared house on All Saints Road in Oxford, Sharp started to accumulate examples from what turned out to be a vast history of the pragmatic use of non-violent struggle. With hindsight, this may not seem such a remarkable idea, but the eventual effect of his researches was hugely significant.

For Sharp, a principled belief in non-violence was necessary for the techniques to work. Yet his research showed that non-violent struggles were overwhelmingly waged by people who did not have ethical or religious objections to violence. He first became aware of this while sitting in a library and examining newspaper accounts of the use of non-violent protest in India. “I was copying by hand descriptions in Indian or English newspapers of what was happening in one of these conflicts. It became clear that the resisters were acting non-violently without that belief. I stopped taking notes. Should I write that down or skip that part? I wrote it down. In time, I realised this was not a grave problem but an immense opportunity. It will not be necessary to convert masses of humanity to believe in principled non-violence before abandoning violence in conflicts.”

Often people who have tried to make change in the past have done so spontaneously, and intuitively. How much more effective might they have been, he wondered, if they’d had a better idea of what had been done before?

He made it his mission to show how effective non-violent political action has been, and how often – not only in the kinds of conflict that can lead to war but even in relatively small disputes. Over several years he compiled a list, which stalled at precisely 198 methods of non-violent action. In his 1973 magnum opus, The Politics of Non-violent Action, Sharp gives examples of each method, drawn from throughout recorded history and all over the world. No 67, “flight of workers”, could be said to have been used by Moses and the Israelites as a way to register their dissatisfaction with the conduct of Pharaoh.

Number 90, “revenue refusal”, was used in ancient China by unwilling taxpayers who buried their possessions and took to the hills when the tax collector was known to be on his way. Number 57, “Lysistratic non-action”, may or may not have been used by women in ancient Greece to end war by refusing to have sex with bellicose men (as Aristophanes suggests), but Sharp found evidence of the same technique being used by women of the Iroquois nation and in colonial times in what was then called Southern Rhodesia. (It was also used in Kenya in 2009 by female protesters who included the wife of the prime minister.)

Some of the techniques appear almost boringly familiar, such as Number 2, “letters of opposition or support”, but they can still be effective, and in certain contexts even that step requires courage. Others require physical bravery, such as Number 171 – “non-violent interjection”, as practised by that anonymous Chinese man who stood in front of the tanks in Tiananmen Square in June 1989. Or Number 66, “total personal non-cooperation”. During the Second World War a conscientious objector in the US named Corbett Bishop declined to eat, dress himself or even stand up. His limp body had to be carried in and out of court and a variety of prison cells. He was forcibly fed by tube. Eventually, after considerable newspaper publicity, he was allowed home without agreeing to anything.

Many techniques require the participation of more than one person. Technique 193, “overloading of administrative systems”, was used to great effect in the US during the Vietnam war and more recently to crash government-run computer systems.

Taken as a whole, the list of 198 methods of non-violent action can be divided into three categories. The first comes under the general heading of “protest”, or “raising awareness”. The second is described by Sharp as non-cooperation – ceasing to have dealings with systems or people you dislike (for instance, not buying items made by companies that exploit their workers, or refusing to fly in order to reduce CO2 emissions). The third group comes under the heading of active interventions to disrupt the status quo, perhaps by building alternatives to what is available. These innovations need not be especially “alternative” in the pejorative sense. Nor are they always negative, in the sense of involving withdrawal or hostility. Japanese trade unions, working for employers who used just-in-time delivery, invented the “go-faster” strike to support their demands for better pay. When in 2011 a library in Milton Keynes was threatened with closure because of budget cuts, local people joined forces to withdraw every single book there, leaving the shelves bare: they opposed the planned closure by showing that they did use the library.

The tactic is so elegant that it appears obvious, even unremarkable, but when we view it in this light we can see the ineptness of others who, out of desperation in a similar situation, might have chosen different tactics – throwing paint over the local mayor, for instance, or embarking on a hunger strike.

Sceptics often say that ordinary people’s nonviolent political efforts “could not have defeated the Nazis”. Rather than get bogged down in debate about whether non-violence “might have” beaten the Nazis, Sharp encourages us to consider how the Nazis were opposed non-violently, both in Germany and in the countries that the Germans occupied. His work provides an impressively comprehensive account of nonviolent resistance to the Nazis, often overlooked by military historians. There are too many instances to list here, but the individual examples aren’t important. The point is that, if it hadn’t been for these setbacks, modest though most of them were, Hitler’s regime might have been even worse than it was. To put it another way: if more people had dared to resist, the Nazis’ worst outrages might have been prevented. To say this is not to pass judgement on people living long ago. It is to challenge ourselves, now. Because it’s easy to imagine that we would have acted boldly if we had been in Germany at the time, but Sharp’s litany of examples challenges us to ask whether there is something that we should be doing today, about something that is going on right now.

The challenge is not delivered in glittering prose. Sharp’s work impresses because of its thoroughness, and its sheer bulk. Professor Thomas Schelling, who won a Nobel Prize in 2005 for his work on game theory, tells me that when they first met in Oslo in the 1960s Sharp gave him “about 800 pages of a manuscript to read on airplanes back to London and back to the US”. Schelling offered Sharp a job at Harvard, partly, he told me, in order that Sharp could shorten the manuscript. In fact, he made it longer.

It was at Harvard that he began to distance himself from his origins on the left, perhaps to make the work more palatable to a mainstream audience, by working with people he might once have shunned. He has never hidden the fact that his work at Harvard was partly funded by the US defence department. “Some people may find either the availability or the acceptance of such funds surprising. I have been arguing for years that governments – and other groups – should finance and conduct research into alternatives to violence.”

One of the students Sharp supervised after settling in Boston was Peter Ackerman, who went on to make a fortune on Wall Street. In 1983, Ackerman invested generously in the new Albert Einstein Institution, with offices on Harvard Square and space for up to 12 people. But a decade ago the two men started to disagree. Ackerman’s focus moved from research to disseminating the work. He set up a new body, the International Centre on Non-violent Conflict, to produce and distribute documentaries, books and computer games that promote non-violent action.

“Gene has been one of the most important people in my life,” Ackerman told me, during a lengthy phone interview, “and created the intellectual foundation for my work. But the important thing is not to deify him – it’s to understand the contribution he made and to understand that the field is now very robust.”

As Ackerman withdrew funding, the AEI’s income dropped from more than $1m a year to as little as $160,000. Sharp’s writing, much of it translated and printed clandestinely, generated little additional revenue. (He still gives much of it away as free downloads.)

Sharp’s commitment to the work, and his never-ending struggle to secure financial support, substantially explain why he never married. “I came close two or three times,” he says, “in my late twenties and mid-thirties, in the US and in Norway. I did regret it, but it didn’t happen. Am I devastated? No. Maybe it’s a flaw in my character.”

He has nephews and nieces scattered widely across the US but sees them only rarely. “Sometimes they will come and stay in Boston. And I talk to them on the telephone once in a while. Do I feel lonely? Yes, but it’s no big deal.” He is uncomfortable talking about his personal life. “People pay too much attention to who I am, as opposed to what I’m saying.”

In 2004, to avoid closing down altogether, he moved the AEI into his house. “We had to get rid of some of our office furniture. We left it on the street for people to take if they wanted it. I knew I would carry on, whatever happened, but it was depressing.” Just one other member of staff came with him. Hired just two years previously, Jamila Raqib had fled Afghanistan with her family when she was five years old. She had graduated in business management, but had her own concerns about the world. (“It was an interesting year, 2001,” she says, with some understatement.) She saw an advertisement for the job at the AEI and applied. “I had not heard of Gene before, nor the institution.”

Raqib was warned that there was no job security, but recently completed ten years working with Sharp. “I’m absolutely privileged to be involved in this work,” she says. “I can’t imagine more important work.” She recognised very early that if she wanted to make a contribution she would have to learn a lot. “I began to read almost everything, the big books and the monographs, and a huge amount of other works that are still unpublished. For a decade or more we had quite a number of fellowships doing this work. There is a lot in the files and there is nobody apart from Gene with that institutional memory.”

Now that Sharp has started to become well known, the AEI is inundated with inquiries from the media and from people seeking advice. They struggle to cope with it all. “I always advise people to beware of foreign advisers – including me,” he says. “People need to understand their own situation, understand non-violence, and learn to think strategically.”

Despite adopting this stance, Sharp has been the frequent target of conspiracy theorists. “That’s because he has reached out, over the years, to military people and to Republicans and to anybody who might give credence to the idea that his work is not a soft, squishy, idealistic, pacifist thing,” says Stephen Zunes, professor of politics and international studies at the University of San Francisco. “Unfortunately, in doing so, he has fed conspiracy theories on the far left that he’s part of a US imperialist plot to create soft coups.”

As Sharp sees it, the methods that he documents can be used by goodies and baddies in - terchangeably. He doesn’t see this as a problem. “In the US, during the civil rights struggle, both sides used these techniques. In the bus boycott, when black people organised car-sharing in protest against segregation, their opponents refused to sell them gasoline and cancelled insurance policies on their cars. I don’t think that was a wonderful thing to do, but it’s certainly better than lynching.”

What he hopes for more than anything else is that people will learn to use non-violent struggle to replace military and violent conflict. “Governments won’t have to fight terrorism any more if the people who might have been terrorists learn to use this kind of struggle instead.” (Among those who have bought his books recently, it transpires, are people who used to be members of the IRA.)

Sharp has never said that every use of every method of non-violent action will bring success. “But people who say it can never work at all seem to use a higher standard of success for non-violent struggle than they do for war. How many wars have been lost, how many people have died in wars without getting the results for which they fought?”

John-Paul Flintoff is an author and journalis

Editor's note: The print version of this article referred to Sharp "holding tenure" at Oxford and Harvard. Mr Sharp tells us that in fact, he studied for a doctorate at Oxford from 1960-1968, and at Harvard he held research appointments in the Centre for International Affairs from 1965 to 1997. The piece has been updated accordingly.