James Joyce was fond of remarking that if Dublin were somehow destroyed it could be rebuilt completely from the account of it given in his' novel, Ulysses. The hundreds of scholars and students that come here for the summer of his centenary year will be walking through a city they already know in their imagination. As they pass under Merchant's Arch they will be aware of the book barrow from which Leopold Bloom purchased The Sweets of Sin, as they pass by Tom Moore's 'roguish finger' they will recall a typical Joycean joke about 'the meeting of the waters'.