Check any decent book on management and it will tell you that a win-win outcome is the only way to achieve a worthwhile agreement through negotiations.
Both sides must be able to walk outside to the assembled media and, more importantly, the people they represent and say "We did very nicely out of that, and here's what we got . . .". Of course the peace process involves so many groups that a win-win isn't possible. What's required is a win-win-win-win-win result.
The Heads of Agreement document is a remarkable piece of work. In 45 lines spread over two pages, it describes a broad outline of what might be the future of Northern Ireland. It does so without being specific because specific proposals would kill off the process instantly. Over the past three years we have seen how every specific proposal produced so far has caused wrangling, walkouts and the collapse of one ceasefire.
Preconditions which don't allow the participants plenty of room for manoeuvre force them out of negotiation mode and into confrontation. So what we now have in the document is a set of propositions rather than positions.
Violence and the threat of the larger paramilitary groupings reaching again for their weapons helped focus the participants' minds. Progress, real progress, that could be seen and understood by everybody was vital. Only through providing this could terrorist regression to violence be prevented. If the peace process is seen to move forward it disenfranchises the terrorists, giving them no justification for their activities. It also tends to cut them off from the already limited support among the general populace they must exploit to remain in business. Without safe houses, training areas and weapons dumps, no terrorist organisation will survive.
Arguably the best demonstration of this approach was by Abraham Lincoln. After the American Civil War, he had a succession of meetings with former leaders, not all military, of the South. Meeting him in the flesh for the first time, they found themselves greatly attracted by his country lawyer accessibility, by his lack of affectation and above all by his humour. Leaving his offices, they often commented on this, much to the annoyance of his own advisers, who took a dim view of him becoming friends with representatives of the Confederacy, and told him so. He expressed puzzlement.
"I thought you would want me to destroy my enemies," he said, smiling his haggard smile and leaving them to work out that the creation of friendships is the most efficient method of destroying enemies.
Our own prison authorities have demonstrated how the win-win strategy works. Republican prisoners have been released and are being released and this week we've seen republican prisoners transferred from Britain to Ireland. Nationalists are able to point to this and say that the process is benefiting them.
In contrast, unionists feel loyalist prisoners in Northern prisons are being ignored. David Trimble proceeded to Mo Mowlam and went directly to Tony Blair. He went so far as to call for Mo Mowlam to be removed. Her reaction was to visit the Maze Prison - a visit which was a political triumph. Precisely what happened during that visit is not clear, but the smart money is on concessions being agreed. Said concessions should become apparent over the coming weeks. So, the republicans win. The unionists win. The process can move on.
A worry has been expressed by the Sinn Fein leadership, and within the pages of this newspaper, that the heads of agreement go too far in appeasing the unionists. This is a misinterpretation of what the document is setting out to achieve. Its first job was to get the parties back to the negotiating table. It has achieved that.
Its second job was to provide opportunities for the participants to win. It is specifically because of their generality that the heads of agreement can achieve this. For example, both sides have been provided with the nebulous idea that they will have their own power-sharing organisations to work with. The North-South Ministerial Council and the Intergovernmental Council can be claimed by the major players as genuine progress. If the precise structures and modus operandi of both organisations had been spelled out, they would have had precisely the opposite effect.
Evidence for that can be found in how representatives of the two governments who most influenced the document's creation have, within hours of it being published, disagreed over its intentions. Mr Andrews claims that the posited North-South Ministerial Council will be entirely independent of the Intergovernmental Council - "a stand-alone institution" as he put it. Dr Mowlam said she would not define it "one way or the other".
Some observers may be tempted to use this disagreement to damn the document. In fact, it demonstrates two very important positives. That the heads of agreement allow plenty of room to manoeuvre to both sides. And that the British government and its representatives in Northern Ireland have seen the error of getting bogged down in pre-emptive discussions of detail.
Motoring analogies have been much in play to describe the events of the last few weeks. First, we had to "kick-start" the process which had "stalled". Then, with the publishing of the heads of agreement, things began to "accelerate". The document itself was described as a "road map to a new agreement" by David Andrews.
A lasting peaceful solution is the intended destination and that seems to be everybody's goal. So the only questions remaining to be answered are whether, with so many hands on the wheel, we will actually get there and how long that journey will take.
Both Mr Andrews and Dr Mowlam have said they believe progress can be made in "weeks rather than months". At the heart of this belief is the conviction that the politicians are getting down to specifics.
In one way they are right. The participants now know the scope of the agreement they are negotiating on and can decide what points they must win and what they are willing to concede to win them.
The last time somebody talked about a solution being achieved by Christmas, Christmas was a few months away. This time we have a year. So long as somebody doesn't completely misread the map, we have a good chance of getting there and bringing with us a gift beyond compare.