THE SENDING, receiving and collecting of postcards was an essential part oflife in Edwardian Dublin. In an age of few private telephones, the postcard was a popular and reliable form of communication - in Dublin there were six mail deliveries a dayand one on Sunday.  To celebrate the centenary of Bloomsday, Niall Murphy has assembled a dazzling selection of 250 postcards, all of them posted in the Dublin area during 1904, four of them sent on 16 June. Here are the messages of ordinary people who walked the streets of Dublin side-by-side with the characters of Ulysses, their words eerily mirroring the novel's events. There is a rescue from drowning in Kingstown, crime and punishment in Grafton Street, the Great Storm of 1903, King Edward's visit, and memories of a 'departed day' spent in Howth. Among the tales of courtship, three are enacted in varying degrees of intimacy - Millicent and Francisque de Boissieu, Jack Miller and Maud Tighe, Ina and John MacGregor - echoing Joyce's use of postcards to establish the blossoming romance between Bloom's daughter Milly and Alec Bannon.  Published in association with the National Library of Ireland, A Bloomsday Postcard features the work of legendary postcard artists: Louis Wain's strange human cats, Lance Thackery's satires of upper-class life, and C. Dana Gibson's exquisite drawings of beautiful women. Here also are cards that depict the Russo-Japanese War, Yukon gold-miners, the Dublin Horse Show and turf-cutters in Connemara, creating a mesmerizing colour mosaic that brings to life Joyce's Bloomsday as never before.