It’s easy to imagine what could have gone very wrong with “In the Bedroom.” Any story about familial loss and grief is prone to slip into a maudlin, soap-operatic mode, whether it’s glossed- up in the style of “Ordinary People” or reduced to the simply bathetic, as in most TV movies dealing with the subject. But it’s also difficult to explain precisely how Todd Field’s debut film (he’s the actor who played, among other roles, the pianist in “Eyes Wide Shut”) avoids all the pitfalls and emerges as powerfully effective and genuinely heartrending. One of the essential elements is the picture’s sense of tastefulness, its refusal to embrace the easy and the overwrought in favor of something more refined. Such an approach, however, could lead to a film that’s decorous but emasculated–we’ve seen that sort of thing before. Another ingredient is the picture’s deliberate pacing, which allows the performers the breathing-space they need to give richness and texture to their characters. Yet that very virtue can result in a film’s becoming self-consciously turgid and obvious. “In the Bedroom” is tasteful and refined, and it moves at a measured pace. Yet it’s not bloodless–beneath its apparently placid surface one always senses the heat of passion. Nor does it come across as at all ponderous–individual scenes are given the space to bloom, and room is made for the skillful use of pauses and silences, but the narrative pulse never weakens. While the dialogue is kept direct, moreover, it retains a realistic feel–tribute to how well Field and co-writer Rob Festinger have worked from the story by the late Andre Dubus. The outcome is a film that’s miraculously simple and spare, yet quietly and astonishingly eloquent and moving. Free of the excesses that ordinarily undermine such stories–even in a final act that might have succumbed to melodrama–while simultaneously skirting the dangers implicit in overcompensating for them, it becomes the most profound and powerful examination of domestic tragedy since Atom Egoyan’s “The Sweet Hereafter” and Paul Schrader’s “Affliction.”

The narrative, set on the Maine coast, is deceptively simple. Frank Fowler (Nick Stahl), a smart, likable kid bound for college to study architecture, is involved with Natalie (Marisa Tomei), an engaging woman about a decade older than he is, not to mention separated from her brutish, threatening husband Richard (William Mapother)–a scion of the town’s richest family–and raising his two young children. Frank’s upper-middle-class parents, Matt (Tom Wilkinson), a doctor, and Ruth (Sissy Spacek), a high school music teacher, have reservations about the relationship–she more than he–but have enough confidence in their son not to interfere overmuch. A sudden burst of violence, however–one that’s characteristically played off-screen–leaves Frank dead and his grieving mother and father stymied in their search for justice. Much of what follows is devoted to an examination of how Matt and Ruth–reticent, emotionally parched people uncommunicative with one another–find their own relationship demolished by their only child’s death and their inability to deal with it, and to their halting attempt to come to grips with the horror of the situation; the manner in which they finally achieve some semblance of resolution–one that is, sadly enough, but a parody of closure–might, in less skilled hands, have become a coarse fantasy of revenge, but here it’s played with a degree of finesse and deliberation that make it seem inevitable and unsettling. (Even the sound of a gunshot is kept real–slightly muffled and ordinary–rather than glamorously loud as in most movies.)

What’s remarkable about “In the Bedroom” is how incredibly right all its creative decisions are. The writing is unerringly genuine, but at the same time neither flat nor pedestrian; even the most charged episodes are played with a delicacy that renders them all the more shattering; and Field employs quiet, ruminative moments with astonishing skill, to add depth without descending into heavy-handedness. He’s helped immeasurably by his impeccable cast. Wilkinson subtly etches a man trying to keep first his joviality and then his anguish within clearly defined limits, and Spacek matches him in her portrayal of a deeply flawed woman unable to endure the devastation she suffers. Tomei gives what’s certainly the finest performance of her career as Natalie–both her easily ingratiating initial manner and her sense of desolation later are entirely convincing–and Mapother is all too persuasive as a menacing lout. As for Stahl, he’s so good that Frank’s presence continues to permeate the film even after he’s physically gone. The supporting cast contributes work so natural and unaffected that they hardly seem to be acting at all.

Overpraise is probably this film’s worst enemy. It would certainly be best if it were allowed to win over viewers stealthily, without their being informed beforehand how exquisite it is, because its virtues aren’t of the highly theatrical sort that will overwhelm audiences who approach it with a chip on their shoulders. “In the Bedroom” is a small, delicate, intimate picture that builds its power through subtle means, working on you gently, almost unobtrusively–much like the pictures of Victor Nunez, with whom Field had an early triumph as an actor in “Ruby in Paradise” (1993). It’s a remarkably assured work which dramatizes the sort of material that’s too often presented crudely and meretriciously with extraordinary purity and integrity. It transcends its genre, the rare tearjerker that honestly earns every drop and sniffle.