By now we know pretty much what to expect from a John Irving novel; since The World According To Garp (his first wildly popular success, and his fourth book), he's held resolutely to a few defining concerns. This is not a criticism. Most writers, once they've found their voices and subject matter, tend to work and then rework a limited set of themes and pet peeves. After all, novelists are by nature obsessive creatures, as they have to be simply to get past the first 50 pages or so of whatever manuscript they're working on, and we all have a fairly limited range of concerns that tend to natter at us. Irving sensiblyùand he is the most sensible of writers, despite his fetish for the quirkyùmakes good use of this condition. His abiding obsession is obsession itself, and his method is to show us how the hearts and minds of a studiedly peculiar cast of characters pulse away very much like our own. He makes the extraordinary ordinary.

This is a lot harder than it looks, particularly when you consider the characters Irving has created over the years and how easyùhow temptingùit would be to hold them up to ridicule or scorn. Think of the tight-end transvestite, Roberta Muldoon, or the pipsqueak prophet Owen Meany. Now, Irving is no saint, and if a group of young women who cut out their tongues in a gesture of victim solidarity happen to come along (the Ellen Jamesians), he'd take them on with wicked glee. Even so, as an unabashedly old-fashioned moralist, Irving works hard at making us care deeply for his people, as much for their failings as despite them.

Irving's other enduring fascination is with damaged body parts, from tongues and penises to throats and wombs. He is the champion of the maimed. The title of his most recent novel, The Fourth Hand, gives a clear enough indication of what limb will be damaged this time around.

The story is told with absolute sureness and authorial confidence. Irving has the most omniscient narrative voice this side of Dickens, and the sense one gets from the first page on is that the universe of the book is unfolding exactly as its creator has planned. Patrick Wallingford is a New York television journalist who works for one of those iffy news networks whose stock in trade is disaster. Charming, intelligent enough to manage the demands of his chosen career, and handsome in an unthreatening sort of way (picture Kevin Costner in the movie version), Wallingford unwittingly finds himself the subject of what will become his most famous story. While reporting on a circus accident in India (an aerialist for the Great Ganesh Circus falls from her trapeze and lands squarely on her husband/trainer; he saves her, but loses his own life in the effort), Wallingford sidles too close to the lion's cage at feeding time, and has his left hand chomped off an inch or two above his wrist.

Meanwhile, in Green Bay, Wisconsin, a woman named Mrs. Doris Clausen longs for a child. Her husband, Otto, who drives a beer truck for a living, is willing enough to do his partùindeed, his wife has a voice so alluring that, when she pitches it in a certain way, it causes men to grow instantly erectùbut the couple can't seem to conceive. In ways neither of them can imagine, their world changes one evening when Mrs. Clausen catches Wallingford's accident on the all-news network. Then and there she determines to donate her husband's left hand to the reporter. The decision quickly evolves into an obsession, which is complicated mainly by the fact that her husband is alive and well.

An unfortunate, if propitious, accident soon changes all that, and the bulk of the novel details the evolution of the unlikely relationship between Patrick Wallingford and Mrs. Clausen. In this instance, the course love follows is decidedly circuitous. There's the issue of Wallingford's promiscuity to deal with (one of the sex scenes, with Wallingford and a young gum-chewing makeup artist named Angie is on a par with the best French farce), not to mention his inability to settle into a single relationship, which makes him a dubious choice for a lifelong partner. For her part, Mrs. Clausen remains deeply in love with her husband, even after his death, and staunchly committed to the intimate and circumscribed world of family and community.

What happens to Patrick Wallingford and Mrs. Clausen? I don't think it's giving too much away to say that hope prevails in the novel; despite the disasters that befall the characters in all of his books, Irving is a celebrant of the world and all its wrinkles. In a certain way, The Fourth Hand can be read as his take on the romantic comedy, with Otto's organ donation acting as, well, Love's handmaiden.

In the novel's afterword, Irving describes how the idea for the plot took hold of his imagination. He and his wife Janet were watching a news item about the first hand transplant in America (more evidence for the truth-is-stranger-than-fiction file, as if we needed it), and Janet asked: "What if the donor's widow demands visitation rights with the hand?"

While many writers are driven by a desire to explore the selfùwhich is to say, their own selvesùIrving is clearly from the "What if" school, and it's this impulse that often gives his work such a compelling loopiness. Curiously, though, despite the bizarre events and coincidences that move this story along, the novel doesn't really have any genuinely startling moments. Actually, the surprise here is that nothing is particularly surprising. I think this may be becauseùif another bad pun can be forgivenùwe know what sort of hand Irving holds just as soon as the first card is played. Throughout his career Irving has used narrative audacity and the confluence of improbable characters and events to jolt his stories to life and render them memorable, but by now we've come to expect this from him, so what once might have seemed fantastic has now become routine.

I'm not sure that this is necessarily a bad thing. Sometimes there's a real pleasure in seeing something turn out exactly as we're led to expect that it will, and I raced through the book in three sittings, engaged as always by Irving's ability to show us how diverse lives and circumstances can and will connect. I don't think a reader is challenged very much hereùhow things happen always takes precedence over why they doùand Irving doesn't really show us anything new about how we muddle through our lives, but probably this isn't the point. The Fourth Hand delivers on its modest fictional promises; it's a species of comfort fiction. ò

P. Scott Lawrence lives in Hudson, Quebec. He is the author of two collections of short stories and a forthcoming novel, Last Light.