I sensed him looking at me as I sat in the tobacco fug of the Palace Bar in Dublin’s Fleet Street back in the ’60s engrossed in Joyce’s Dubliners. His scrutiny from the adjacent bar stool was unsettling. Suddenly, without apology, he tapped his finger on the page and nodded at me, signalling silent approval of my choice of book. Fixing my eye, he asked: ‘Did you ever hear of O’Brien?’ I shook my head. ‘Now there’s a hard man who runs Joyce close,’ he said. Then, pausing for dramatic effect, he added portentously: ‘And it was in this very bar he’d be drinking.’ Flann O’Brien, who loved to parody pub conversations, would have relished the bathetic conclusion. But I owe to that chance acquaintance a great debt. Over the next hour, he introduced me to the writing of a drunk and waspish comic genius who stretched the boundaries of literary invention and became a legend of Irish letters.