In June 2000 my husband Liam Clarke - the former Belfast Telegraph political editor who died at the end of 2015 - and I decided to write our unauthorised biography of Martin McGuinness.
We had been commissioned to submit ideas for biographies of leading figures in the peace process. It was no contest who we would go for.
McGuinness is the most fascinating, complex and enigmatic individual to have emerged from the Troubles. But there were hurdles in our way. Republicans as a group aren't best known for sharing information, but McGuinness was noted for being particularly reclusive, private and secretive.
As the opening quotations show, and as history tells us, there are at least two very separate faces to Martin McGuinness.
So, we split the work roughly in two. Liam, then working for The Sunday Times, would work backwards focusing on McGuinness's political influence and growth. I had a better knowledge of Derry and the Troubles; I got the early years.
And that's how it largely stayed. I had done a lot of work on the murder of Mountbatten, so I wrote that chapter, whereas Liam, who had written a book on the hunger strike (Broadening The Battlefield: H Blocks And The Rise of Sinn Fein) hopped back a decade to focus on the prison struggle and Sinn Fein's subsequent politicisation.
It worked well. In the meantime our publisher, Mainstream, was pushing for a title to promote the book. As we jointly wrote the final chapter, we couldn't decide on how McGuinness would be remembered.
In November 1999 Ulster Unionist leader David Trimble warned the IRA that it must disarm otherwise there would be no ruling administration in Northern Ireland: "No guns, no Government means just that."
That quote was like a shaft of sunlight suddenly shining through the clouds. Not only was Martin McGuinness: From Guns To Government a great title, it was also the key to understanding the man.
There is an old Italian saying: 'One hand washes the other, and they both wash the face'.
McGuinness cannot be understood without a realistic and critical assessment of his role as IRA man, officer commanding Derry, director of operations for GHQ staff, and one time chief of staff of the IRA.
But since the early days of the Troubles McGuinness had simultaneously been on another journey - from his meeting as part of an IRA delegation with Conservative Secretary of State William Whitelaw in Cheyne Walk in 1972, to his secret meetings with MI6 man Michael Oatley, which started in 1973 and continued until Oatley's retirement in 1991.
The Roman god Janus is the god of beginnings, transitions, and endings. He presides over the beginning and ending of conflict - war and peace. McGuinness has been there all the way.
He joined the IRA in Derry during the early Troubles. He was a leading IRA man on Bloody Sunday, January 30 1972, when 13 unarmed civilians were shot dead by the 1st Battalion of the Parachute Regiment. One man died several months later from his injuries.
When he gave evidence before Lord Saville at the Bloody Sunday Inquiry he was Sinn Fein's chief negotiator. He confirmed in his statement to the inquiry that he was second-in-command of the IRA in Derry at the time of the Bloody Sunday shootings, the first time he had acknowledged his membership.
At the time he was also the Education Minister in the Assembly. Giving evidence in November 2003, McGuinness denied a claim by the British agent 'Infliction' that he had fired the first shot on the day. However, the inquiry nonetheless found that McGuinness was "probably armed with a Thompson sub-machine gun, and though it is possible that he fired this weapon, there is insufficient evidence to make any finding on this".
Admitting to his IRA role was a shrewd move by McGuinness. He had no option. He had told Dublin Special Criminal Court on October 29, 1973: "I have been a member of the Derry IRA for two years and I am very, very proud of it."
Released from the Curragh in 1974, he had just been appointed director of operations on GHQ staff when he was again arrested and sent to Portlaoise jail after being convicted of IRA membership. He was released in November 1974.
He had condemned himself out of his own mouth. However, by saying that he had left the IRA in 1974, a claim few believed, he had constructed a crafty alter ego for himself - the trusted peacemaker with an impeccable history of IRA activity.
It was a history, as Eamonn McCann pointed out, that had seen the Derry Brigade of the IRA under McGuinness's command "bomb the city centre until it looked like it had been hit from the air".
But it would be wrong -deeply and fundamentally - to cast McGuinness as some kind of republican Robin Hood.
No account of McGuinness's legacy is complete without recognition of the thousands of victims of the IRA.
From Franko Hegarty to Joanne Mathers, from Lord Mountbatten to Mary Travers, there is no doubt that McGuinness could shed a light on the circumstances surrounding many of the deaths of the troubles.
When he gave evidence before Lord Saville, McGuinness refused to either confirm or deny any details of individual IRA men or operations, quoting the previously unknown IRA "code of honour".
His silence marks a failure of the peace process to secure prisoner releases to a truth recovery process and amnesty.
By July 2000, 428 terrorists, including 143 serving life sentences, had been released from the Maze Prison.
Mass killers and bombers, both loyalist and republican, many responsible for the worst atrocities during 30 years of violence in the province, walked free to be welcomed by cheering supporters.
It was the biggest missed opportunity of the peace process.
But it is not too late - for either McGuinness or for any other former combatant.
Although the Belfast Project (the Boston College tapes), where former terrorists gave taped accounts to researchers to be released after their deaths, is still the subject of court proceedings, it is open to any one of us to record our memoirs, to set the record straight, and to lodge such an account with a trusted associate.
McGuinness may have already lodged such an account.
Certainly, he has demonstrated both vision and courage in the past, and the IRA 'code of honour' would prevent anyone releasing details of his past during his lifetime.
But the families of the victims who are still desperately pursuing clues for the motives behind the attacks on their loved ones, who are still haunted by imaginings of how they lost their lives, and most of all those families of the Disappeared, deserve the truth, no matter how brutal that may be.
The god of war and peace is usually depicted as a two-faced god, since he looks at both the future and the past.
Janus presided over the beginning and ending of conflict. Master of transition, the doors of his temple were open in time of war, and closed to mark the peace.
Think of the legacy that Martin McGuinness, as Deputy First Minister and former IRA leader would leave, if he were to announce, in the few weeks that remain before the next Assembly election, that Sinn Fein and the IRA are prepared to belatedly discuss a truth recovery process.