Tens of thousands of official government papers are being released to the public today under the 30-year disclosure rule.
The memos, letters, and notes, which are held in the national archives, cast new light on the workings of the Irish State in 1975.
The documents made public today reveal that secret plans were drawn up to cater for 100,000 refugees from the North if the Troubles worsened and security deteriorated.
Officials were asked to examine refugee situations in Pakistan, Palestine and Cyprus as part of their preparations for a possible exodus of Catholics from the North in the event of increased violence.
Elsewhere, the newly released papers also reveal that military intelligence kept files on current, previous and future cabinet ministers in 1975, as well as political parties, trade unions, women's organisations and journalists.
The politicians targeted included former Labour minister Conor Cruise O'Brien, a trenchant critic of the Provisional IRA.
Elsewhere, a declassified file from the Department of the Taoiseach reveals that former trade unionist Phil Flynn was kept under surveillance during the IRA kidnapping of Dutch businessman Tiede Herrema, even though he had been asked to mediate in the affair.