THE effect is stunning.

I walk down a flight of stairs, through a set of doors and WB Yeats speaks to me loudly, unmistakeably.

He talks of Innisfree, of a small cabin made of clay and wattles, of hives and bees and linnets.

I listen, adapting to the reality that the greatest Irish poet has been preserved on tape and The Lake Isle of Innisfree is one of the readings that will be played on a loop as I wander around the exhibition in the National Library of Ireland in Dublin that celebrates the 150 years of his birth. The mystical poet would rejoice at his voice echoing down the ages. He was fascinated by mysticism and occultism. He was an attender of séances.

The ethereal voice is thus fitting as is the location of the exhibition. More associated with Sligo, the Nobel Prize winner has a history at the National. Above the exhibition lies the reading room where he studied and wrote, outside lies Kildare Street where he first met James Joyce, genius, heretic and the writer of the most debated, most loved, most despised guide book in the world.

If Yeats was standing on pavements grey thinking of waters lapping at Innisfree, Joyce was already contemplating creating a new writing, describing a familiar landscape in an extraordinary day.

In October 1902, they convened at the library before heading to cafe. Yeats was 37 years old, with a substantial body of work behind him and greatness waiting to be conferred upon him by literary juries, critics and readers. Joyce was 20 years old and was destined to live in exile, his extraordinary fame coming after his death, the undisputed literary garlands destined to decorate his grave rather than to be placed on his thin, hunched shoulders.

The most conspicuous result of Joycean labours is Ulysses, a chronicle of the events of June 16, 1904 in Dublin. It is part myth, part examination of the human condition in its evocation of Leopold Bloom whose day and thoughts it recaptures, part revolutionary writing, more than part incomprehensible, at least to this reader, and mostly and increasingly beguiling as age tempers frustration and leads the reader to the acceptance that not everything needs to or can be understood.

''In the broadest sense it could technically be used as a guide to the city," says Mark Traynor, manager of the James Joyce Centre that stands on the other side of the Liffey from the National Library. Ulysses has bequeathed Bloomsday, an annual event that draws obsessives, eccentrics and the merely curious to Dublin to follow in the footsteps of a Joycean hero on June 16.

My arrival has coincided with another day of some import in Ireland. The preparations for St Patrick's Day include milling through tens of thousands of people, and that merely to order at the bar. My purpose, though, is to celebrate the importance of Yeats and Joyce and to appreciate that a superficial yet instructive view of their life and work can be achieved without joining the tours that will draw up to 8000 people to Bloomsday this week.

My tour is individualistic and parts of it unfold by chance. Yet the presence of Yeats and Joyce is testified at every staging post. The journey starts at the National Library where their friendship began. It continues down on to Nassau Street, over the Liffey and beyond. A pop on the open-top bus is useful for one stop-off, but it is not necessary. This is a walk rather than an expedition.

The jaunt can be completed in a day, Bloomsday or any other, and offers an exercise that is gentle but much in the way of an understanding of a city and what formed and concerned two of the greatest writers of the 20th century.

The first step is to spend time exclusively with Yeats in the National Library, listening to his voice and that of others, including Sinead O'Connor, who read his poetry as his life unfolds in a series of setpieces around a deftly curated exhibition.

Out in Kildare Street, one can either head down to Nassau Street where Joyce first met his wife Nora Barnacle on June 10, 1904, or cut across to Grafton Street where Bloom subsequently meandered and Yeats once strolled in search of books. I prefer Nassau Street as it evokes memories of a crucial encounter in Joyce's life. There, in the words of Richard Ellmann his brilliant biographer, he encountered Miss Barnacle of Galway, "a tall young woman, auburn-haired, walking with a proud stride''. She was to remain faithful to Joyce in all his trials and impervious to the attractions of his books, though she knew both to her cost and to her satisfaction that she lived with a genius in chaos and in occasional happiness in Trieste, Zurich and Paris.

The next staging post is to cross the Liffey and head for the General Post Office, the site of the uprising that will be commemorated in gargantuan style on its centenary next year.

One can pause in front of the statue of Cuchulainn and reflect on the words of Yeats that "All changed, changed utterly/ A terrible beauty is born.''

Blood, death and destruction was the price of freedom from British rule. Yeats was conflicted about the uprising, Joyce was distant in thought and in body. He was in Zurich when the post office was seized by republicans who were later shot at Kilmainham Jail. This scene can be reached by jumping on an open-top bus at the top of O'Connell Street and a tour reveals that Joyce and Yeats were not alone in their initial tepid reaction to Easter 1916.

Yeats, and the Irish populace at large, were energised and outraged by the subsequent executions, most pitifully the shooting of James Connolly while strapped to a chair because his injuries would not allow him to stand. Yeats did not publish Easter 1916 until five years later but his strength of feeling can be gauged by the realisation that he wrote Sixteen Dead Men, The Rose Tree, and On a Political Prisoner in quick succession.

The GPO conflagration would have had another significance for Joyce. "Ulysses is an incredibly detailed representation of the city at a particular moment in time," says Traynor. "Joyce famously said that if the city was one day destroyed it could be rebuilt from the pages of his book."

O'Connell Street was largely destroyed during the uprising though Ulysses has grown to a monumental height. "The reputation too of Joyce has evolved," says Traynor, sitting in an attic at the top of the James Joyce Centre which is but a short walk from O'Connell Street.

"He was once condemned as a pornographer and it was not really until the 1980s and the centenary of his birth that he was widely celebrated," says Traynor. "The first Bloomsday was in 1954 but it has grown into something strange and oddly wonderful. It may have appealed to something in Joyce because he was a relentless self-promoter."

He and Yeats, though, were also Irishmen who found differing ways to address their concerns, to assuage the itch of their genius.

"I suppose Yeats created new symbols over what it meant to be Irish while Joyce reacted against the traditional by looking inwards. Joyce wanted Ireland to be part of a global network," says Traynor. "He admired Yeats but believed cultural nationalism was stultifying and restrictive. He was concerned with the idea of exile."

Just up the hill from the James Joyce Centre lies Belvedere College where the author of Dubliners and Portrait of a Young Man was schooled for a time. It is my vantage point the day after my individual literary daunder for the St Patrick's Day Festival that starts on the streets below.

The garish, raucous and unashamedly joyous parades seem a distance from the writers and their preoccupations. But this is a story of short walks. There is surely something to link St Patrick's Day to the greatest chroniclers of Irish sensibility.

Yeats would have surely smiled at the symbolism while Joyce just may have taken solace in the presence of hundreds of thousands of visitors who are a reminder that exile can be temporary and is only ever physical, never spiritual.

Hugh MacDonald travelled to Dublin as a guest of Failte Ireland