Oliver St John Gogarty (August 17, 1878-September 22, 1957) was an Irish physician and surgeon, who was also a poet and writer, one of the most prominent Dublin wits, and for some time a political figure of the Irish Free State. He is perhaps now best known as the inspiration for Buck Mulligan in James Joyce's novel Ulysses.
Born in Dublin, Gogarty was a medical student and joker who wrote humorous verse and stories. His verse was admired by W. B. Yeats. He had a strained relationship with Joyce that ended when Joyce left Ireland; Gogarty claimed a gun was involved. One of his best known bits of doggerel, The Ballad of Japing Jesus, was quoted in the first chapter of Ulysses.
In later life, he moved widely in British society, and the USA. He died in New York City.
Robot Wisdom's Joyce Page (http://www.robotwisdom.com/jaj/ulysses/gogarty.html)