The Cairn of the Headland

James O'Brien is an Irish-American academic who specializes in the history of Medieval Ireland - a subject on which he is highly well-informed and about which he has a passionate feeling of partisanship. He speaks Gaelic fluently, can read ancient Irish manuscripts and inscriptions in the original, and is thoroughly familiar with such works as The Book of Leinster, The Great Book of Lecan and The Annals of the Four Masters.