Julia Glass’s new novel springs, in a roundabout way, from an episode that took place in her first book, “Three Junes,” in which a music critic dying of AIDS bequeathed his pet parrot to a bookstore-owning neighbor on Bank Street in Greenwich Village. From that pact, a brief but momentous friendship was born.

Those two characters — the critic, Malachy Burns, and the bookstore owner, Fenno McLeod — were wonderfully rich creations who stole the show in “Three Junes,” which won the National Book Award in 2002. Fortunately, Glass was not ready to be done with these personalities. Fenno went on to appear in her second novel, “The Whole World Over,” and here he is again in “And the Dark Sacred Night,” her fifth, along with Malachy, although this time both men play subdued if still pivotal roles.

None of this back story is essential for readers new to Glass’s fiction. Her latest book is fully enjoyable on its own. But those who are familiar with her work may find fresh appreciation for the fugue-like way in which Glass constructs her tales. Characters and themes wind in and out of the action, sometimes taking center stage, other times filling out the chorus. Her books call and respond to one another as her characters do, their relationships broadening and deepening over time.

It was Fenno’s great misfortune, he realizes years after the fact, that he met Malachy at the end of the music critic’s life, when Fenno “hadn’t even realized what it was he’d found until he had managed to lose it.” The loss of Malachy, who died 20 years ago at age 38, has been profound for everyone who knew him, and his influence has maintained its power in the decades since his death.

One of the people most haunted by Malachy had never even met him. He is this book’s protagonist: Kit Noonan, a 40-something ex-professor of art history who lives in the Jersey suburbs with his landscaper wife and their 9-year-old twins. Kit has been miserably unemployed during the two long years since he failed to qualify for tenure. The bills and credit-card debts are mounting, as is his wife’s exasperation. At last, she delivers an ultimatum: Kit must use this idle time to solve the lifelong mystery of his paternity. His mother, unwed at the time of his birth, has steadfastly refused to tell him who his father was. Find out some other way, Kit’s wife demands, so we can all move on.

I’m spoiling nothing by revealing, as Glass does early in the narrative, that Kit’s father was the very young and bewildered Malachy Burns, who met Kit’s mother, Daphne, in the late 1960s in Vermont at a summer camp for musical prodigies. Each of these ardent teenagers had dreams of a solo career — Mal played the flute; Daphne, the cello — but fate had other plans. Daphne returned to New Hampshire pregnant with Kit and, while raising him, eventually became a high-school music teacher. Mal, who had just begun to define his sexual identity, regretted the brief encounter with Daphne, cut off all communication, and found success as a music critic in Manhattan until his all-too-early death from AIDS in 1989.

Kit’s quest to discover what we already know begins with a visit to his ex-stepfather, Jasper Noonan, a Vermont outdoorsman and ski-shop proprietor whom Daphne married when Kit was 9 and divorced a decade later. Glass has a particular talent for inventing believable old people: Like Percy Darling in her previous novel, “The Widower’s Tale,” Jasper, now 72, is gratifyingly multi-dimensional — rueful and humorous, prickly and practical. In turn, Jasper leads Kit to Mal’s parents, Zeke and Lucinda Burns, elderly, distinguished Vermonters (Zeke is a state senator) who introduce Kit to the rest of his father’s large family. Eventually, Kit’s search leads him to Fenno McLeod, now nearly 60, still living in Greenwich Village with Mal’s parrot and happily involved with Walter Kinderman, the garrulous restaurateur whom readers first met in “The Whole World Over.”

Depending on their relationship, each of Mal’s relatives and friends feels his loss differently. For his mother, the time since his death has only moved her grief “to a more distant room. When she enters that room, though she does so less often, the pain still blinds her with its keen, diamondlike brilliance.” For Fenno and Walter, Mal represents, among other things, a vanished generation. As survivors of the AIDS-plague years and “curators of lost lives,” they feel guilty for the luxury of growing old gracefully. And Kit, who will always know his father only by association, “worries that he is unable to feel sad enough. Too often now, he wonders what it is he should feel.”

Even with so much bereavement at its core, Glass’s novel, like all her fiction, is the opposite of maudlin. This memento mori is as much about the teeming, glad business of life as it is about grief — “the bright blessed day,” as the Louis Armstrong song puts it, as well as the dark sacred night. It’s a big, messy, imperfect book that mirrors the messy imperfection of contemporary life, stuffed with hot-button details (from Greek yogurt and fair-trade coffee to gay marriage and grandparents’ rights), and sprinkled with small convincing moments of joy.

Rifkind is writing a book about the screenwriter Salka Viertel.

And the Dark Sacred Night

By Julia Glass.

Pantheon. 379 pp. $26.95