Many years ago on a Good Friday in Dublin – one of the two days of the year when the bars are shut in Ireland – a friend of mine found a pub in the city centre that opened discreetly for regular customers. He went there at noon, fell into good company and began to enjoy himself. By around four, however, having drunk too much, he repaired to the gents and vomited copiously. Once he had finished, he discovered to his consternation that, in the confusion, he had lost his false teeth; he had flushed them down the toilet. He returned to his associates and explained his dilemma by opening his mouth. There was much discussion about what could be done until one of his friends made a phone call, and, within an hour, a man who worked for Dublin Corporation knocked quietly at a side door of the pub. He had in his possession a map which he spread out on a table. It was a map of the sewers of Dublin.
Having had a few drinks, he and a few others, including the dentureless one, set out and moved along main streets and side streets until they came to a manhole. The fellow from the corporation lifted the manhole and climbed down a ladder inside. After an interval of five minutes or so, he reappeared with a triumphant look on his face and a pair of dentures in his hand. My friend was so relieved that he put them back in his mouth forthwith. Since they had served him well through the years, he saw no reason to defile them by running them under a tap. He was a scholar as well as a gentleman, and he lived to be old.
Karl Whitney's ingenious and affectionate book about Dublin manages to tell us a great deal about what lies under the city – sewers, tunnels, hidden rivers – without bothering to deal with the cliches about the city's marvellous pubs, or the better-known monuments, or indeed the antics of the citizens that some foreigners might find either alarming or amusing. Since he was brought up in Tallaght, one of the new suburbs to the west of the city, Whitney's interest is in creating a map of the places that have become the real Dublin for most Dubliners. He keeps an eye out too for the traces left in the new suburbs of an older landscape, with bits of monasteries and medieval walls and ancient river beds lurking uneasily among all the concrete and urban expansion.
This city of Whitney's has appeared in the work of poets such as Thomas Kinsella, Eavan Boland and Paula Meehan, and in the novels of Roddy Doyle and Dermot Bolger, but it has always had the status of the semi-official, the almost secret; it is absent from postcards and guide-books. His book makes a useful companion not only to David Dickson's magisterial Dublin: The Making of a Capital City, published earlier this year, but also to Michael Rubenstein's extraordinary book Public Works, which places public utilities in Dublin such as water, gas and electricity at the centre of the work of Joyce, Beckett and Flann O'Brien, among others, allowing urban engineering and modernist literature to exist in a symbiotic relationship.
Whitney is not one of those travel writers who tells you all about themselves. He seems a modest sort of fellow, amused by the world, with a keen eye for its oddness. He walks a lot; his book has a good chapter on the bridges over the river Liffey and another on the many houses where the family of Joyce lived. He rides his bicycle. He also takes buses, and relishes the desire paths that make up the city's bus routes. As a non-Dubliner, I find these routes more puzzling than anything else in the city; Dublin buses, arriving in twos and threes, seem to lurch constantly in directions that no one had, as far as I can make out, ever foreseen.
Whitney talks to urban archaeologists, experts on sewage systems, community leaders. He has a way of capturing someone's tone without seeming to make too much effort. Since every Dubliner is meant to love the chimneys of the Poolbeg power station near Sandymount Strand, it is a relief to hear the chairman of the Half-Moon Swimming Club refer to them as the "awful bloody chimneys". Whitney's own tone tends to be direct and factual, thus when he allows himself a poetic moment, it tends to work, as in a single sentence paragraph such as: "Part of writing about a place is imagining what it might be like if it weren't there at all."
It is impossible to write about the creation of the new Dublin suburbs without dealing with the vast amount of corruption and graft which went into the rezoning of land, and the relationship between greedy builders, bad planners and politicians. Perhaps the gritty sense of life, the raw amusement at things that Whitney captures in the new parts of Dublin arises from the knowledge that thought and ingenuity went into the creation of these extensions of the city, much of it directed at making builders and politicians rich. There is nothing better for your prose style, or your dry sense of humour, than the feeling that the building of the very room you are in helped the bank balance of a well-known public figure.
Whitney visits half-finished housing estates, including Adamstown: "Of the 10,000 units originally envisaged, 1,400 had been built and 1,249 had been occupied by December 2012. The yawning vastness of the void – the sheer volume of negative space left by the underdeveloped stretches of waste ground – dwarfed the inhabited sections of the site, making the houses feel huddled together on the frontier of a dark and impenetrable wilderness."
He goes also to see Priory Hall, a development created by an ex-IRA man, that the residents had to vacate because the planning authority allowed builders to regulate themselves. The builder could thus sign off on what was a flood-trap and a fire-trap. When Whitney asked a woman who took out a mortgage on an apartment in Priory Hall what she wanted to happen, she replied: "I think it needs to be knocked to the ground."
Like most European cities, Dublin has become a tourist destination, with the tourists crowding to the same places, places associated with a myth of the city that the actual inhabitants find ridiculous or inexplicable. I, for one, have never understood why you would listen at length to the story of brewing Guinness, which is what the many visitors to the Guinness Brewery in Dublin do, even on hot days. Nor have I ever understood why you would, willingly, want to see Trinity College, but I might be alone in that.
It would be great then if the Americans and the Germans who come to Dublin in large numbers, and claim to love the city, had Whitney's book in hand rather than, say, Ulysses, or some official guide book, and began to pay attention to the city's underground rivers and its great unfinished estates, not to speak of the strange bus routes and the many holes in the ground, the hidden and essential life of Dublin.
• Colm Tóibín's new novel, Nora Webster, is out on 2 October from Viking. To order Hidden City: Adventures and Explorations in Dublin for £13.59, go to bookshop.theguardian.com or call 0330 333 6846.
