FORTUNATE LIVES By Robb Forman Dew Morrow. 285 pp. $20

AT ONE POINT in the early chapters of this superb new family novel by the award-winning author of Dale Loves Sophie to Death, young David Howells's girlfriend casually observes that the Howells' residence is her favorite place in the world. "It's like a visit with the world's last happy family," she remarks -- and I can't think of a better way to characterize the wonderfully happy experience of reading Fortunate Lives.

Not that the Howellses -- David, his younger sister Sarah, and their parents Dinah and Martin -- haven't had their fair share of unhappiness, and then some, since the tragic death of older son Toby in a car accident. Fortunate Lives begins six years later, in the uneasy summer before David is slated to leave his family's home in the small New England town of West Bradford for his freshman year at Harvard. Dinah, especially, is having trouble adjusting to her son's impending departure. She can't even formulate a short statement she's been asked to write to David's freshman dean. "Of course, we're biased," one of her first attempts starts out, "but we think Harvard is really lucky to be getting our son David Howells . . ." Well, yes. But what to say about David himself? She can't decide.

Moreover, Toby's death still casts a long grim shadow over the entire Howells family, however well they appear to have adjusted. Now that Dinah is in a sense about to lose David as well, her unresolved grief over Toby returns to flood her with "shockingly intense sorrow and an unwarranted feeling of desolation and loneliness."

Robb Forman Dew's story gathers slowly, at first, like a Berkshire Mountain summer. But don't be misled by the leisurely pace of the first third of the book; every sentence in it counts, and with the arrival of Netta Breckenridge, an incredibly literal-minded young single mother and visiting professor at the local college where Martin Howells teaches, the ordinary tensions of any family, happy or otherwise, are exacerbated to the danger point. Netta is a marvelously repellent creation: militantly humorless, self-centered and outspoken to the last degree. No sooner does she set foot in the Howells' kitchen, for instance, than she lights into good-natured Dinah for a perfectly innocent remark. "I really find unconsciously sexist remarks more and more intolerable," she reprimands her astonished hostess, who's just complimented Netta's small daughter on her good looks.

It would be a shame to give away the ensuing entanglements, sexual and otherwise. Suffice it to say that they're equally intriguing, believable and unpredictable. There's no question that Dinah suffers most from the conflicts that result. "The thing is," she writes to David's dean in an ongoing series of imagined letters as moving as they are funny, "I'm losing too much. I'm having to let go of things that I need . . . I've let a good many things go out of my life without bitterness, with no thought of revenge. But I'm being pressed to the absolute limit, and it seems to me that Harvard College ought to take this into consideration in the future."

Fortunate Lives is a strongly character-driven story, but shrewdly plotted, as well, like a Jane Austen novel with a contemporary, sexy spin. If there's a slight drawback to Dew's narrative approach, it's an occasional tendency to over-analyze the Howellses at the expense of the action; but the insights are so sympathetic, so acute and so just, I soon came to relish them nearly as much as the beautifully crafted scenes.

Fortunate Lives is a book about coping with death, separation and the inevitable, hard changes all families must confront over the course of a lifetime. In a deeper sense, it's also a celebration of family love, enduring friendships, and common human decency. There are fine set pieces you'll want to read again and again, including a memorable description of the town of West Bradford. There are hilarious and revealing anecdotes -- my favorite involves a feud between two elderly professors over, of all things, their amorous pet dogs. And there are those surprising and idiosyncratic details, on every page, that are the gifted novelist's hallmark, from the uncannily accurate lilt of teenagers talking together out of the presence of adults to the "warm, tidal scent of dogs in hot weather."

As a reviewer, I admired Robb Forman Dew's new book immensely. But merely saying that doesn't really do justice to it, so I'll end on a personal note. As a parent of college-age children myself, I found the Howellses as appealingly recognizable as any characters I've encountered in recent years. Fortunate Lives is a superior story, luminous with intelligence and wit and affection, written straight from the heart of one of our most accomplished contemporary novelists.

Howard Frank Mosher is a Vermont novelist whose books include the recent "A Stranger in the Kingdom."