Deaglán de Bréadún, author of “Power Play: the Rise of Modern Sinn Féin,” is former Northern Editor of The Irish Times. During his time as Northern Editor, de Bréadún witnessed the historic IRA ceasefire of 1994 and the birth of the peace process proper.

He did not just witness these events. De Bréadún was the only journalist who correctly predicted when the ceasefire would happen, a real tribute to his ability to engage Republican sources at a time when most journalists were still steering clear because they had the untouchable stigma.

De Bréadún did his job the old fashioned way and, thus, his new book on the rise of Sinn Féin is incredibly important for putting in perspective the party's amazing rise to the top. Just a few years ago Sinn Féin struggled to hold two percent in elections North and South.

Now they are at around the 20 percent mark in the south, and the largest nationalist party and in power in the north.

Quite how that happened is the source material for a very good book and de Bréadún has written it.

Former Taoiseach Bertie Ahern launches Power Play The Rise Of Modern Sinn Fein @Hodges_Figgis @IAP_MERRION

— Peter o connell (@Peterocmedia) October 20, 2015

That knocking sound concentrating the minds of the leaders of the Republic’s main political parties right now is a growing number of Sinn Féin potential ministers at the doors of power, doors that were once insuperably closed to them.

Sinn Féin’s rise is perhaps the most remarkable political story of our generation, and in this masterful account Deaglán de Bréadún presents the definitive outline of the party’s long path to power north and south of the border.

Those who wish to halt Sinn Féin’s rise refuse to accept that they are no longer at war, no longer the political wing of the “armed struggle” carried out by the Provisional IRA.

But that long campaign was declared definitively over by the Independent Monitoring Committee (IMC) established by the Irish and British governments and confirmed by the commissioner of the Garda Síochána.

So from being what de Bréadún calls “the Provo’s brass band” the party has turned into something altogether more unanticipated by Dublin – a left wing political model that has a real chance of wielding significant power on both sides of the border in this century, a key player.

Current polling suggests the party will give Fine Gael a serious run for its money in the next general election, but whether it has a prospect of entering government in a major way in the Republic is still in play. Chances are it may take one more election especially if, as expected, the Labour Party is decimated and Sinn Fein leads the left.

Deaglan De Breadun speaks at the launch of his book Power Play - The Rise of Modern Sinn Fein @IAP_MERRION

— Peter o connell (@Peterocmedia) October 20, 2015

What is clear is that the old attacks on the party have gained no traction and the party recovers from every charge leveled at it. De Bréadún advises us that we should countenance that fact in the coming elections.

Equally he contemplates the unforeseen effects its coming to power could have both north and south of the border. The party’s slogan is “Tiocfaidh ar lá” (Our day will come) and it appears to be finally coming true for them he writes, but perhaps not quite in the way they originally expected.

"Power Play the Rise of Modern Sinn Féin" by Deaglán De Bréadún, Merrion Press, $24.99. Available on Amazon.