Cities are not only anonymous, they are ultimately indifferent in the way that a small town can never be, and if, as one of the characters in "Echoes" says of Castlebay, a seaside resort on the coast of Ireland, "People would never die of loneliness, as they might in a big English city; but attitudes could be cruel, and tolerance was low . . . families couldn't cope with what they called 'shame and disgrace.' "

When terrible things happen, as terrible things will, the news must be contained, for if it seeps out into the town it will settle like soot on the family name, defining it for generations. They will become the Doyles whose daughter was sent away to have an illegitimate baby, or the O'Haras whose father was much too fond of a jar, or the O'Briens whose brother got into trouble with the law. All achievements will be striped with the shadow of that shame, and the townspeople, in extending sympathy to the fallen, will feel themselves raised up.

Simply, "Echoes" is the story of Clare O'Brien, a shopkeeper's daughter, who falls in love with and marries the son of Castlebay's doctor. It is not, in the eyes of their town, an equal alliance. It doesn't matter that Clare's brilliance and hard work have earned her a scholarship to a Dublin university. In neat little Castlebay, there is a place for everyone and everyone in his place. Clare, in climbing out of hers, has messed things up and made people unsure how to respond.

In bare outline, it is a standard situation in popular fiction. Will the heroine be accepted by the family and friends? Will she prove to be not only their equal but their superior?

But Binchy has written a broader and a better book. While Clare and David are at its center, the wings are so full of interesting and sympathetic characters that "Echoes" becomes not just the story of two lovers but of a town.

Dancing along the edge of the plot and somehow defining it is Gerry Doyle, a man of irresistible and inexplicable sex appeal. Though born and bred in Castlebay, Gerry is the outsider; he serves the same purpose as the strange gunfighter in old western movies who rode into town, brought into the open things that people had hidden and then, at the end, was gone.

Angela O'Hara likes to think of herself as an outsider, a brilliant teacher drawn back to Castlebay to care for her ailing mother. She proves her distance by making wisecracks about the very reverend and very bossy Sister Immaculata and by aiding Clare in her attempts to leave Castlebay behind. But Angela, kind, sympathetic Angela, turns out to be merely eccentric, a woman who has laid claim to the right to be different but who learns to her regret that she cares very much what the town thinks.

The true outsiders, the people who come to Castlebay in the summer, touch the town barely at all. They merely point up the poverty of a community that must make most of its living from 11 weeks of tourist trade. "Clare watched it all from the shop. It was like a different world to her, these carefree people with different clothes every day . . . they were always laughing and the boys all stood round and laughed too . . . They seemed to have endless money . . . Imagine having so much pocket money that you didn't even have to think before you bought things . . ."

Clare scrambles to get out of Castlebay, studying her books in bed at night, fighting off the harassment of her relentlessly unpleasant sister. (When Clare tries to retrieve a miserable Christmas by insisting that the family tell a round-robin ghost story, sister Chrissie begins, " 'Once upon a time there was a ghost that had this desperate sister. It had four brothers who were all right but it had a really terrible sister . . .' "

The tight community of Castlebay with its fierce and shared Catholicism is darkness. Dublin is looseness and light where "even side streets, even lanes were lit up. And shops had their lights on in windows all night so that you could go and look at what they had for sale." But like Angela, Clare has to leave the light and return to Castlebay. In that narrow community she must learn that not all sins flow from the flamed life of the sinner; some come out of impossible situations and when you go looking for the villain, you may only find a victim.