As anyone who’s spent an uncomfortable weekend with relatives knows, a few days are more than enough to recapitulate decades of familial resentments. And a Fourth of July holiday in 2005 holds the potential for greater conflict than usual in Joshua Henkin’s new novel, “The World Without You.” Four generations convene at Marilyn and David Frankel’s western Massachusetts summer house to observe the one-year anniversary of their son Leo’s death. A journalist, Leo was abducted and murdered in Iraq. His mother publicly refused President Bush’s invitation to the White House and has spent the subsequent year writing angry op-ed pieces about the war. She’s also angry at gentle David for “trying to make the best of an unspeakable situation.” As the novel begins, we learn that she is leaving him after 42 years of marriage.

Their three daughters and Leo’s widow don’t yet know about the separation, but each is toting plenty of baggage to the Berkshires in addition to her suitcases. Thisbe, flying in from California with Leo’s son, is reluctant to tell her in-laws that she has a new boyfriend. Eldest sibling Clarissa is so desperate to get pregnant that she and her husband stop at a hotel en route from Brooklyn to have joyless sex (because she’s ovulating). Lily, driving up from Washington, is stuck picking up her sister Noelle at the Boston airport. These two younger sisters have never liked each other, and Lily is openly contemptuous of Noelle’s embrace of Orthodox Judaism as “just another installment in [her] random life.” Lily isn’t the only member of this liberal, assimilated family bemused by Noelle’s transformation from a wild teenager into a Jerusalem housewife who twice voted for Bush.

Henkin skillfully unpacks these various back stories in his opening chapters, setting the stage for the dramas to come. Yet despite a couple of stormy scenes, “The World Without You” is essentially a quiet, reflective book. Henkin is a pleasingly old-fashioned novelist who takes his time in exploring his characters’ emotions and their fraught connections to one another. The intricate bonds of family were the subject of his previous two novels, “Swimming Across the Hudson” and “Matrimony,” but he widens his focus here to encompass multiple points of view, drawing us into the thoughts of almost every adult in the extended clan.

But Henkin never lets their story turn into a debate about the war in Iraq or the merits of Orthodox Judaism. What interests him is the texture of everyday existence and the constantly shifting human relationships embedded in it: the slip of the tongue over a child’s name that stakes a grandmother’s claim, the collective solving of a crossword puzzle that infuriates a slower-witted in-law, a brutally competitive tennis match that unexpectedly reconfigures the family dynamic. Those who have resorted to such passive-aggressive tactics with their own relatives will laugh and wince in recognition at Henkin’s perfectly calibrated measurements of intramural jockeying.

So it’s appropriate that “The World Without You” closes with understated moments of adjustment, small steps that signal the family members’ movement towards acceptance of a larger truth so basic that it’s a cliche: Life goes on. A quick glimpse two years later suggests that some of the wounds inflicted by Leo’s death have healed, or at least scarred over. But Henkin doesn’t maneuver his characters into grand declarations of reconciliation or reassessment. Instead, he gives several of them an engagingly modest mantra that expresses the unpretentious philosophy of his warm-hearted novel: “We could try.”

The World Without You: A Novel by Joshua Henkin (Pantheon)

Smith, a contributing editor of the American Scholar, reviews books for The Washington Post, the Los Angeles Times and AARP.

The World Without You

By Joshua Henkin

Pantheon. 336 pp. $25.95