'The Stranger's Child" is a long novel about a mediocre poem.

Not the most inspiring summary, true. But Alan Hollinghurst constructs masterful fiction from seemingly flimsy premises. His previous novel, 2004's "The Line of Beauty," starred a shallow hanger-on in conservative London society, yet its depth of insight was sublimely Jamesian. Few novels so skillfully revealed what's really said behind polite facades, and "The Stranger's Child" displays that talent on a broader canvas.

The poet is Cecil Valance, who shortly before World War I visits Two Acres, a British estate owned by the family of his college lover, George. For them to even hint at their homosexuality would be scandalous, and Hollinghurst stresses the anxiety that shadows their affair. (George can only call it a "mad vertiginous adventure" to himself.) Still, Cecil's wit and sense of freedom electrifies everybody he meets. That includes George's 16-year-old sister, Daphne, who's smitten when Cecil dashes off a poem, "Two Acres," in her autograph book.

Fast-forward: The war is over and Cecil is dead at 25, shot by a German sniper. Daphne has married Cecil's brother Dudley. And the poem endures: One man says it "will be read for as long as there are readers with an ear for English music, and an eye for English things."

Critics (and Dudley) aren't so impressed. But the world won't let go of Cecil. As the novel leaps across the decades, readers eagerly parse his writing, his relationships, and his sexuality. Chief among them is Paul Bryant, who in the '70s and '80s researches a biography of Cecil, inspired by his own sexual liberation. But Paul is a poor interviewer with a narrow agenda, and those who knew Cecil won't -- can't -- speak. "He was asking for memories, too young himself to know that memories were only memories of memories," an elderly Daphne thinks, exasperated.

Of such fumblings are literary reputations made. Hollinghurst is a superior novelist of manners, and the brilliance of "The Stranger's Child" is in how it reveals the ways bad blood and secrets muck with history. When everybody strains to say the appropriate thing, the facts suffer. That theme is perfectly suited for Hollinghurst, who can reveal a host of hidden messages in the simplest utterance (or pursed lips).

These are better times: We can more openly express the feelings George and Cecil had to obscure. But "The Stranger's Child" is a cautionary tale. What we've gained in candor we've lost in appreciation for fine art; we have more books but more gossip. And it's still hard to name those hard-to-express emotions, Hollinghurst tells us, which is why Cecil's poetry endures. It's why psychologically penetrating novels like "The Stranger's Child" should last, as well.

Mark Athitakis is a reviewer in Washington, D.C. He blogs at americanfiction.wordpress.com.