Dublin is celebrating its millennium. Never mind that the city's thousandth anniversary was actually more than a hundred years ago, in 1840. The Irish have never been ones to let a little historical imprecision, or much of anything else, get in the way of a celebration.

This year's bash, which includes some of the most ambitious projects ever undertaken in the Irish capital, commemorates not the founding of the city but a mere victory over Viking invaders by a semi-obscure Irish princeling in 988. The victory didn't materially alter the course of Irish history, but it did have the pertinent benefit of having happened exactly 1,000 years ago, thus allowing Dublin to take part in the recent craze among European cities for discovering a timely link with the past and then cashing in on it. As I say, never mind.

The city is spending a lot of money sprucing itself up, planting trees, preparing special exhibitions and opening new attractions, making what was already one of Europe's most friendly and agreeable capitals more appealing still. And that is not to be mocked.

At the moment, all this progress is chiefly manifested in the form of disruption. As of late January, the National Museum was effectively closed for remodeling; Grafton Street, one of the principal shopping thoroughfares, was in the disorderly process of having its asphalt torn up and replaced with bricks; and many of the city's hundreds of superb Georgian buildings were obscured with scaffolding.

If all goes according to plan, these and other related preparations should be completed by March 17, St. Patrick's Day, when the celebrations get underway in earnest. Everywhere you turn you are confronted with a city that has suddenly taken an interest in itself. Among the more ambitious projects of this anniversary year will be the biggest street party the city has ever attempted, culminating in a massive fireworks display on July 9; the opening of a new museum, the Viking Adventure Center; special film, music, theater and literary festivals; and the most lavish St. Patrick's Day parade the city has ever seen.

Almost a quarter of Ireland's 4 million inhabitants live within greater Dublin, but the city seems much smaller. It has the contented air of an overgrown market town, and a pace of life to match. It is a city without subways or skyscrapers, and the closest it comes to a rush hour is a certain quickening of the step when the pubs open.

The relaxed and genial atmosphere is neatly counterpointed by Dublin's formal squares and elegant Georgian architecture, which dominate the heart of the city. The late 18th century was Dublin's heyday, and the period is forever recorded in its architecture. The central geographical feature of Dublin life is the River Liffey, which splits the downtown as it proceeds in a stately manner from the Wicklow Mountains at the city's rear to the broad sweep of Dublin Bay. Its slow-moving waters, as dark and as beguiling as a pint glass of Guinness stout, have inspired countless Dublin writers from Jonathan Swift to James Joyce.

North of the Liffey is O'Connell Street, a broad avenue along which stand several of the city's biggest stores and hotels as well as the main tourist information office. But the real heart of the city lies half a mile away, across the river in a small and curiously nameless district bounded roughly by Trinity College, Merrion Square and St. Stephen's Green, a city park of inexpressible allure, with broad lawns, tidy flower beds and a large pond full of skimming swans.

Here and on the narrow neighboring streets and squares you will find the city's students, bankers, politicians and media people all going about their business with an air of unhurried informality. Here too you will find the best-preserved of the city's architecture -- indeed some of the finest Georgian architecture anywhere in Europe. There is block after block of handsome red brick buildings, three stories high, all of them offering a pleasing unity of style, with plain windows and exteriors but bold front doors, which are usually painted in rich primary colors, with delicate rounded windows above them. The best of these are to be found around Merrion Square, whose many famous residents included the poet William Butler Yeats and the parents of Oscar Wilde.

Running between Trinity College and St. Stephen's Green is the pedestrians-only Grafton Street, the most fashionable shopping thoroughfare in Dublin. Two places of particular note on Grafton are Bewley's Oriental Cafe, a Dublin institution since 1927, where a pause for coffee and cake is an essential part of many a Dubliner's day, and Brown Thomas, which sells a wide range of upscale keepsakes ranging from Waterford crystal to Belleek porcelain and tweeds from Donegal.

On nearby streets are most of the city's museums, as well as many of its best restaurants, hotels and pubs, tucked in among the elegant Georgian row houses. Most of these have now been converted to offices, but they continue to lend the face of Dublin a unity few other cities enjoy. Because of this unity the intrusion of modern buildings is often discordant.

In fact, Ireland has sometimes been lax in defending its heritage -- it is still virtually the only European country that does not routinely fund the rescue and restoration of historic buildings -- but developers themselves are showing greater sensitivity, and shopkeepers are being encouraged to remove plastic signs and give their shopfronts a more traditional look. These policies are already having visible effect.

The west front of Trinity College, looking across to the stern pile of stone known as the Bank of Ireland and up the pleasing sweep of street called College Green, is possibly the single most rewarding architectural view in the city. In the middle of the Trinity building's facade is a wooden door. It looks private, but don't let that deter you. It's actually the main entrance to the campus. Pass through and on the other side you will find yourself in a sudden pocket of serenity, a large courtyard cobbled with uneven stones and presided over by venerable-looking trees.

In a building off to the right (clearly signposted) is the university's greatest treasure: the Book of Kells, a richly ornamented manuscript handwritten by monks at an unknown Irish monastery in about A.D. 800 In 1953 the book was split into four volumes, two of which are now always on display under glass in the library's magnificent Long Room, a cathedral of a room, 209 feet in length with a high vaulted roof and bookshelves rising magisterially from floor to ceiling. Containing 200,000 ancient leather-bound volumes, it is worth a visit.

The one other compulsory attraction in this part of town is the National Gallery of Ireland, on Merrion Street, next door to Leinster House, the home of the Irish Parliament. The museum contains more than 2,000 works of art from all over Europe and from all different periods. Many are by artists you may never have heard of -- Wouter Knyff, Govert Flinck, Bartolome' Murillo -- but they are no less fabulous for that, and the collection includes a lavish sprinkling of old masters. A particularly helpful touch is that alongside many of the works are fairly detailed descriptions of what the pictures depict, how and why they were executed and in what ways they differ from others of their periods. Admission is free, incidentally.

The museum's central staircase serves as a kind of national portrait gallery, its walls lined with paintings of eminent Irish men and women. No city in the world has produced more great writers than Dublin. Consider the roll call: Jonathan Swift, James Joyce, George Bernard Shaw, Oscar Wilde, Richard Brinsley Sheridan, Brendan Behan, John M. Synge, William Butler Yeats, Patrick Kavanagh, Sean O'Casey. And all in a city with a population about the size of Albuquerque's.

Yet, apart from their portraits in the National Gallery, there is precious little in the city to commemorate its incomparable literary heritage. There is a small James Joyce museum at suburban Sandycove (open only from May 1 to Sept. 30), but in Dublin itself not a single home of any writer is open to the public as a museum. Happily, spurred by the millennium celebrations, plans are afoot to open a museum dedicated to Dublin writers, but this won't be ready before 1990 at the earliest. In the meantime, tourists of a literary bent must content themselves with strolling around the city and looking at the houses of the famous from the outside.

This is easy to do for two reasons. First, Dublin is remarkably compact. And second, the Irish Tourist Board produces a number of first-rate guidebooks to help you find your way around. I particularly commend "Tourist Trail: A Signposted Walking Tour of Dublin" (75 pence from the main tourist office at 14 Upper O'Connell St.), which leads you on a three-hour tour through the city, pointing out notable homes and other sites that most travelers would otherwise overlook and giving quite a lot of incidental history and anecdote en route.

One of the more admirable aspects of this tour is that it takes in not only the more picturesque quarters, but also many of the tenement neighborhoods, where you are visibly reminded that Ireland is one of the poorest countries in Europe, with a per capita GNP barely 60 percent that of the EEC average. The most interesting and accessible of these poorer neighborhoods is the Liberties, the area around the city's two cathedrals, Christ Church and St. Patrick's -- both of which, incidentally, are Protestant. Surprisingly, Dublin doesn't have a Catholic cathedral.

North of the river you will find some occasional green parks and little squares, but mostly just a succession of mean streets and dank shops, some barely large enough for a proprietor and a single customer. Just off Constitution Street, for instance, behind the imposing headquarters of the Irish legal profession known as the King's Inns, is Henrietta Street, a whole block of splendid 200-year-old homes, once veritable mansions, now abandoned and rotting.

Nearby, and in a rather better state of repair, is Parnell Square, home of the Hugh Lane Municipal Gallery of Modern Art, a splendid free museum, much lighter and cheerier than the National Gallery across town and containing many notable works, including some excellent Constables.

The Tourist Trail walk can be broken into two halves, and the suggested time scale of three hours (total) doesn't include time spent lingering in the museums -- or pubs -- along the way.

As for pubs, they are the very lifeblood of the city. There are literally hundreds and hundreds of them -- two or three on every block, often more -- and they are almost without exception warm, friendly, crowded, smoky and inescapably appealing. Among the more famous are Davy Byrne's (21 Duke St.), which features in James Joyce's "Ulysses," though now it is more a cocktail bar for yuppies than a traditional pub; the Brazen Head (20 Lower Bridge St.), the oldest pub in the city; O'Donoghue's (15 Merrion Row), for live music; and William Ryan's (28 Parkgate St.), for its unspoiled interiors.

All pubs tend to get very busy in the evenings -- at O'Donoghue's the bartenders sometimes stand on stools to pass drinks over the heads of people at the bar -- especially on weekends. If you are looking for a relatively quiet drink, and a 50-50 chance of being able to sit down, I can recommend Larry Murphy's at 43-44 Lower Baggot St.

The Tourist Trail guide points out some of the more famous pubs along the way, but if you really want to get serious about Dublin pubs -- and there are worse things to get serious about -- you should get hold of the book "Ireland's Pubs," by Sybil Taylor, which is widely available in Dublin stores and gives diverting histories of many of its finest drinking spots.

Even if you don't drink, the pubs are so much a part of the life and spirit of the city that you should pop into one or two for a soft drink, just to soak up the atmosphere and savor the conversation. You never know, you may even find yourself inspired to write a literary classic.

Bill Bryson, who lives in Yorkshire, is currently working on a book about the English language for William Morrow. MILLENNIUM MADNESS

There are at least 150 special events in Dublin this year connected with the millennium celebrations. Among the more notable happenings:

St. Patrick's Day parade, March 17. Always an important event, this year it will be bigger and better than ever, with 100 floats, more than 1,000 drum majorettes and at least 100,000 spectators lining the parade route through the heart of the city and up O'Connell Street. Starts at 11 a.m.

Viking Adventure Center, opening St. Patrick's Day. A re-created street scene showing Dublin life as it was in 988 A.D., along with other exhibits tracing the Viking era in Ireland. At St. Audoen's Church, High Street.

Millennium Walking Tours, May 15-Oct. 15. Special two-hour guided walking tours tracing 1,000 years of Dublin's history, three times a day Monday through Saturday and once on Sunday. Meet at the Millennium Office on Royal Hibernian Way, off Grafton Street.

Dublin Delineated, June 1-Sept. 30. An exhibition of drawings and other documents surveying the changing face of Dublin over three centuries, National Library, Kildare Street.

Dublin -- the Writers' City, June 13-26. A two-week literary festival of lectures, readings and plays at various venues throughout the city, all aimed at celebrating Dublin's enormous contribution to literature.

Dublin Music Festival, June 17-19. Annual feast of choral music in the National Concert Hall.

Millennium Street Carnival, July 9. The biggest street party ever held in Dublin, with wandering musicians, entertainers, clowns, open-air concerts, food stalls and the like all over town. The culmination will be a massive fireworks display (either at Dublin Harbour or St. Stephen's Green).Dublin Theater Festival, Sept. 26-Oct. 9. Annual festival of plays, by new and established Irish playwrights, and by companies from all over the world. Details of productions will not be released until June.

Emerald Isle Classic American Football Game, Nov. 19. West Point takes on Boston College in the first match between American college teams on Irish soil, at Lansdowne Road Stadium, Ballsbridge.

WAYS & MEANS

GETTING THERE:

Aer-Lingus, the airline of Ireland, flies from New York's John F. Kennedy International to Dublin daily except Tuesday. There is a stop en route at Shannon in western Ireland. Pan Am currently is flying on Wednesday and Saturday only from New York's JFK to Shannon with a connecting flight on to Dublin. Northwest currently is flying on Wednesday only from Boston to Shannon with a connecting flight on to Dublin.

Air fares vary by season. Aer-Lingus is quoting the following round-trip fares to Dublin from Washington (via a connecting flight to JFK): Through March 31, $517; April 1 to June 14, $617; June 15 to Sept. 14, $717; Sept. 15 to Oct. 31, $617. These tickets require an advance purchase of 21 days and are good for a minimum stay of seven days and a maximum stay of six months.

Several charter airlines generally offer flights from Boston or New York to Shannon or Dublin between May and September. Round-trip rates from New York are expected to range from $400 to $450, depending on date of departure. For more details, consult a travel agent.

There are many flights daily to Dublin from major cities in Great Britain and the rest of Europe. Year-round auto ferries cross the Irish Sea to Dublin from Liverpool and Holyhead in England. You can catch a train or motorcoach from London and other cities in England, Scotland and Wales to the ferry ports. There is a year-round ferry from Le Havre in the north of France to Rosslare Harbor, south of Dublin.

GETTING ORIENTED:

The assistants at the central tourist information office at 14 Upper O'Connell St. are outstandingly helpful, and will find a room for you for a charge of 50 pence. The office also has a bureau de change and a good range of books and pamphlets. But be warned that it shuts on Saturday afternoons and all day Sunday -- when you are actually most likely to need it.

GETTING AROUND:

In Dublin this is no problem. Almost all the major attractions are within a mile of each other, though bus services throughout the city are frequent and efficient. For forays further afield, CIE, the national transportation company, offers a variety of special bus and rail passes. Tickets and information are available from the central bus station on Amiens Street, behind the Custom House. Taxis do not cruise looking for passengers as in other cities, but there are taxi ranks every few blocks.

WHERE TO EAT:

Restaurants tend to be slightly expensive though seldom outrageous. The Buttery Brasserie on Royal Hibernian Way, off Grafton Street, serves excellent, mostly French food at reasonable prices (about $15 per person, including a service charge). For those on a budget, Beshoff's at Westmoreland and O'Connell streets serves delicious fish and chips in pleasant surroundings for about $5 per person. Take note that most restaurants are closed on Sundays and plan ahead.

WHERE TO STAY:

Hotels and guest houses are not as numerous as in other European cities, so at busy times, such as around St. Patrick's Day, reservations are a good idea. Bear in mind also that ferries from Britain and mainland Europe tend to arrive late at night, when finding a room isn't easy. I stayed in the Georgian House, at 20 Lower Baggot St., which was nicely decorated and conveniently located, but decidedly hit-and-miss on hot water. A single room with bath and breakfast starts at about $44, but a 10 percent service charge is loaded on top. At the top of the scale is the Shelbourne, on St. Stephen's Green, where a single room, without breakfast, starts at about $160. For bargain hunters, the North Strand youth hostel, at 49 North Strand Road, charges only about $6 a night and is highly regarded by the young, though it is difficult to find.

PUBS:

Pubs are open 10:30 a.m. to 2:30 p.m. and 3:30 p.m. to 11 p.m. on weekdays and Saturdays, 12:30 p.m. to 2 p.m. and 4 p.m. to 10 p.m. on Sundays.

INFORMATION:

Irish Tourist Board, 757 Third Ave., New York, N.Y. 10017, (212) 418-0800.

Bill Bryson