”The Poser,” by Jacob Rubin (Viking)

Giovanni Bernini, the narrator of Jacob Rubin’s wonderful debut novel, is both a mirror and a sponge. As soon as he meets people, he feels the urge to become them. His imitations can be both a form of flattery and an act of insult. But try looking for the real Giovanni behind all the voices and postures he assumes and you’ll soon be as lost as he is. The result is a slippery meditation on the nature of identity delivered with vaudeville verve.

Rubin sets “The Poser” in an alternative United States (never named) in what feels like the 1950s. As it opens, we learn that Giovanni has made a stage career of his eerie talents.

“Gestures are a costume,” he says, and every guise contains what he calls a “thread.” “Pulled by the right hands,” he asserts, “it will unravel the person entire.”

Back in high school, Giovanni’s urge to ape everyone around him used to land him in detention. But he had an ally who came to his rescue every time: his beloved Mama. Her boy’s only problem, as she sees it, is that he’s “sympathetic to the bone.” Mama shares her son’s fascination with the “thread.” However, there’s a lot about her own life — including the whereabouts of her husband — that she withholds from him.

After Giovanni is discovered by a grubby but effusive talent agent, he swiftly goes from school troublemaker to major theatrical draw in a city resembling Manhattan. With the help of theatrical entrepreneur Bernard Apache, “the man who would ruin my life,” Giovanni is catapulted further to screen stardom. Later, he’s even lured into the world of politics, where he’s far more invested in rhetorical style than in any actual ideas.

There are bumps along the way, including Giovanni’s frustration at his inability to master the thread of Lucy Starlight, an alluring chanteuse who becomes his lover. And it doesn’t take long to divine that there’s something unsustainable about his act.

Rubin’s most daring narrative move comes in the final quarter of the book, when Giovanni, with the help of the calm and canny Doctor Orphels, tries to get to the bottom of who he is and what makes him tick. Was Mama, with all her encouragement, helping him or sabotaging him? And is impersonation really the best way to understand “the insides of another person”?

“The Poser,” as it follows Giovanni from triumph to perilous triumph, seduces you with its fanciful prose, its larger-than-life characters and its fun-house-mirror take on a land of opportunity where appearance often trumps reality. It’s also one heck of a way for Rubin to announce his own presence on the literary stage.

Michael Upchurch is the former staff book critic for the Seattle Times.

THE POSER

By Jacob Rubin

Viking. 242 pp. $26.95