"The Burgess Boys," by Elizabeth Strout Stories of marital relations - strained, destroyed or restored - surely take up a larger section of our fiction shelves than stories of brothers and sisters. Yet why should that be, given the deep imprint siblings can make? Staying intimate with one's spouse is a challenge, certainly, but the problems posed by a difficult brother or sister can be just as painful. In Elizabeth Strout's fluid and compassionate new novel, "The Burgess Boys," her first book since the Pulitzer Prize-­winning "Olive Kittredge," the connections among Jim Burgess and his younger twin brother and sister, Bob and Susan, are central to the story. That the ­marriages of these adult siblings are either over or in a rocky state is kept in the background of a narrative primarily concerned with the affinities and enmities played out among these three during a family crisis. At the start of the novel, the "boys" happen to be together in Brooklyn, where both live, when Jim receives a desperate call from their sister. A sour, divorced optometrist, Susan still lives in Maine, where they were all raised, with her 19-year-old son, Zach, and an elderly female lodger. Zach has gotten into some serious trouble. Shirley Falls, a depressed former mill town with a substantial influx of Somali refugees, was also the setting of Strout's first novel, "Amy and Isabelle." Susan's son, a shy, friendless boy who works at the local Walmart, has thrown a frozen pig's head through the door of a local Somali mosque - "During prayer. During Ramadan. It was, he explains, just "a dumb joke" (and one that appears to be based on an actual incident that occurred in Lewiston in 2006). The boy will be arrested and, in a community fraught with new racial tensions, may well be prosecuted for committing a hate crime. His two uncles - Jim, an extremely successful and famous defense lawyer at a high-end Manhattan firm, and Bob, a die-hard liberal who works for the legal aid society - offer to help steer him and his mother through the catastrophe. Complicating the family's ability to cooperate are animosities that vibrate constantly at a low, painful pitch. Jim routinely belittles his younger brother, calling him "slob-dog" and "knucklehead." Susan, who has disliked her twin from way back, hardly manages to be civil to him, even when he comes to assist her (in one bitter moment, she even mocks him for his childlessness). Affable Bob - who is, like Susan, divorced - appears the most tolerant, though it gradually becomes clear that he considers his aggressive brother a jerk and his sister narrow-minded. All are marked by their father's sudden death when they were young children, in an accident whose contours become better defined over the course of the novel. If Bob is the book's conscience, Jim is its operator, though the perspective also shifts to include Jim's patient, proper ­Connecticut-born wife and Bob's ex-wife, who illuminate other sides of the Burgess boys. Bob is the main source of empathy for the Somali refugees, though Strout attempts to give broad scope to the difficulties of merging two diverse and ­beleaguered populations. A white cop tells Bob the Somalis are "whackjobs," and in Susan's curt opinion the town's chief of police "doesn't give a doughnut's damn about the Somalians." A Somali man grimly recalls that the policemen laughed when they first caught sight of the bloodied pig's head in the mosque. Yet the police chief, who briefly dated Susan in high school, self-importantly stages a news conference, and an ambitious lawyer in the attorney general's office takes steps to pursue the hate-crime charge. Strout, trained in the law and married to a former Maine ­attorney general, covers the case with easy clarity, ever alert to the intersection of personal politics and legal strategy. The Somalis struggle with displacement in scattered scenes that Strout sets within that community. Can these traumatized families find a place in the United States, specifically in the rugged, unforgiving countryside of Maine? At what cost to their sense of selves, or of home? In an affecting counterpoint, Strout chronicles the Burgesses" attitudes toward their own homes. Susan stubbornly keeps her sparsely furnished house underheated, but a greater warmth infuses it as she befriends her elderly lodger. Jim sneers at Bob for his "graduate dorm" living, but Bob's own feelings are poised between relief at the anonymity of apartment dwelling and an existential dread when his squabbling downstairs neighbors move out and he catches sight of their desolate, empty rooms. The blank walls seemed to say wearily to Bob: Sorry. You thought this was a home. But it was just this, all along. Jim, whose luxurious Park Slope brownstone matches his ostensibly perfect family life (kind, devoted wife; three grown children, all in college), finds out how wrong it is to take such elegant stability for granted. There is a geographic extension of the Burgess boys" rivalries in the complex tensions between Mainers and New Yorkers, and it's hard to think of anyone more convincing on this subject than Elizabeth Strout. Tough, blunt Susan bears some resemblance to the magnificent Maine character of Olive Kittredge. The brothers themselves have divided emotions when it comes to their old home: the familiar landscape makes Bob "unutterably happy," while Jim finds the bleakness "unbelievably depressing." The Burgesses" mother suffered a trip to New York only once, and Susan, when she finally braves a visit, finds the place crowded, baffling, appalling. Strout handles her storytelling with grace, intelligence and low-key humor, demonstrating a great ear for the many registers in which people speak to their loved ones. If there's a weakness here, it's Zach, offstage for much of the action in spite of being the catalyst for it. He may be hollow, but he seems a basically nice kid, a teenager who doesn't appear to possess the kind of hatred (or, frankly, imagination) required for the pig's head stunt. Perhaps Strout's point is that an act of aggression against strangers will be sternly addressed by our legal system, flawed though it may be, while hostilities against one's own flesh and blood are more in the ordinary run of things. These disputes must be worked out privately, in the homes and corridors of family life. Sylvia Brownrigg's novel for children, "Kepler's Dream," written under the name Juliet Bell, will be published in paperback next month.