Hidden Ulster, Protestants and the Irish Language is a book by Pádraig Ó Snodaigh published in 1973; revised editions appeared in 1977 and 1995.
Ó Snodaigh argued there had been a strong tradition of Gaelic-speaking among the Ulster Protestant planters in the 16th and 17th centuries.
[1] Ó Snodaigh hoped a shared linguistic heritage would thus improve relations between Northern Ireland's antagonistic sects during "the Troubles".
[2] The book was strongly criticised by the British and Irish Communist Organisation, which saw it as a Social Democratic and Labour Party-inspired attack on their Two nations theory; Ó Snodaigh replied to their criticisms in subsequent editions.
[3][4] The book was also criticised by the Democratic Unionist Party, but praised by Fortnight Magazine and some members of both the Orange Order and the Ulster Volunteer Force.