Sir Dermot MacDermot (1906–1989), self-styled Prince of Coolavin, Chief of the Name, head of the MacDermot clan, and a descendant of the Kings of Moylurg.
MacDermot attended Stonyhurst College as a lad, and went on to Trinity College, Dublin, where he was elected a Scholar.
Sir Dermot MacDermot had served as British Ambassador to Indonesia (1956–59) and Thailand (1961–65). He succeeded his brother as The MacDermot upon the latter's death in 1979. His outstanding achievement towards the Macdermot clan was his definitive account of the family, "MacDermot of Moylurg: The Story of a Connacht Family". It is commonly held to be one of the best - if not the best - books dealing with the origins, history and descent of a Gaelic family. At over five hundred pages it chronicles in depth yet with clarity the affairs of the Kings of Moylurg and their neighbours over the course of six hundred years, and the story of many different MacDermot families from the time the kingdom ceased to exist up to the 20th century. It contains thirty-five family trees concerning MacDermots and their related families, and ten fascinating appendices.
Dermot died before seeing the book in print, but it was published shortly after by his sons Niall (who succeeded him as Prince of Coolavin) Hugh and Connor.