Erskine Hamilton Childers ( 11 December 1905 -- 17 November 1974 ) , was the son of Robert Erskine Childers ( author of the spy thriller The Riddle of the Sands . Erskine Hamilton Childers ( 11 December 1905 -- 17 November 1974 ) served as the fourth President of Ireland from 1973 until his death in 1974 .