Just to set the record straight, and I'm sure everyone already knows this - the Republic of Ireland is a country in its own right. Its predominant religion is Roman Catholic. Northern Ireland (or 'the six counties') is part of Great Britain; it has large Catholic and Protestant communities. The Troubles that you will all remember from the 1970s concerned a small part of Northern Ireland. Although this is a vast oversimplification, the RC communities in NI generally want to join the Republic and have what they would call 'a united Ireland'; the Protestants are generally much more keen on staying part of the UK. In the 1970s, the nationalist IRA (Irish Republican Army - therefore Catholic) was particularly involved in terrorist activity to try to gain independence, and the loyalist Protestants (led by such people as Ian Paisley) were equally active in fighting back. The British army was sent in to keep the peace, especially in certain very volatile areas of Belfast. There was a huge amount of bloodshed on all sides, much of it by innocent civilians. The terrorism spread to mainland Britain, with many bombings in London, Birmingham and other centres.
Despite its name, Northern Ireland only covers a small part of the north of the land mass of Ireland. For example, Donegal and Galway are in the geographic north but are part of the Republic, not NI. Many Northern Irish terrorists fled over the border from time to time and holed up in deserted farms, etc in Donegal especially. The border - which could not, of course, all be policed, as most of it is open countryside, was an extremely dangerous place during those years. If you wanted to travel on one of the main roads between NI and the Republic, you were subject to massive security checks; the checkpoints were concrete bunkers with machine guns on top of them.
If you meet people from NI and the Republic, they have very different accents, although it would be true to say that Dublin (capital city of the Republic) has a very different accent from the south - eg Co Waterford - too.
Just thought I would clarify things. I still have no idea who this author is!!!
Rosemary