In addition to his writings, Ó Criomhthain also provided content for Father George Clune's lexicon of the Munster Irish dialect, Réilthíní Óir.

Their son Seán also wrote a book, Lá dar Saol ("A Day in Our Life"), describing the emigration of the remaining islanders to the mainland and America when the Great Blasket was finally abandoned in the 1940s and 1950s.

He began to write down his experiences in diary letters in the years after World War I, following persistent encouragement by Brian Ó Ceallaigh from Killarney.

[11] Traditionally viewed as more a cultural ethnography than a work of literary merit, this stance has been challenged in recent times by scholars such as Mark Quigley.

The Flower translation of the text concludes with a statement whose final clause is well known and often quoted in Ireland:I have written minutely of much that we did, for it was my wish that somewhere there should be a memorial of it all, and I have done my best to set down the character of the people about me so that some record of us might live after us, for the like of us will never be again.The first of the so-called "Blasket autobiographies", the release of An tOileánach in 1929 was followed by the release of Muiris Ó Súilleabháin's Fiche Bliain ag Fás in 1933 and Peig Sayers' Peig in 1936.