What compels us to love an antihero? This question hounded me as I read “Gabriel’s Moon,” the new spy novel by William Boyd. I contemplated two curmudgeons from the espionage genre: Thomas Fowler of “The Quiet American” and Rick Blaine of “Casablanca.” In these stories, Fowler and Blaine undergo transformative character change. Their dormant hearts are awakened; they realize they cannot be idle bystanders to injustice. We cheer for the redemption of the dapper grouch.

No such catharsis for another beloved antihero type: iconoclasts like John Yossarian of “Catch-22” and Ignatius J. Reilly of “A Confederacy of Dunces.” Instead, their contrarianism highlights the hypocrisies of their societies. As I kept pulling the thread, ever more complex antiheroes came marching to mind: Batman and Lebowski, Fleabag and Cromwell — a parade of disaffected loners, some redeemed, others condemned, all their stories etched into my heart.

There are countless ways to love an antihero. So why do I so loathe Gabriel Dax?

“Gabriel’s Moon” opens in 1960 in London, where Gabriel is a successful young travel writer. On a jaunt to the Democratic Republic of Congo, he interviews Patrice Lumumba, the new prime minister. Lumumba insists Gabriel tape their conversation, during which he names the three foreign agents plotting his downfall. When Lumumba is subsequently assassinated, Gabe’s tapes become the hottest potato in the hemisphere.

What ensues is a familiar espionage comedy: the man who knows too much. Gabriel is incessantly ruffled, coaxed, felt up, shaken down and otherwise manipulated by players far more dexterous than he.

Lucky for Gabe, these players are mostly women he’d like to shag. There’s Faith Green, a British spy boss of “confident, mature beauty,” and Nancy-Jo Berndlinger, an American student recruited by the C.I.A. to seduce and destroy. Poor little heroin-addicted Nancy-Jo — “waif-like and needy,” “febrile and pretty”; you can practically hear the old-timey ambulance sirens in the distance when she simpers into Gabe’s life.

Boyd leads us onward, from Southwold to Warsaw, coursing out the clues like a seasoned storyteller. But though the breadcrumbs may be artfully strewn, the meatloaf of a man at the center of this farcical repast is decidedly half-baked. Gabriel — “the tall gaunt handsome one … he’s a very good writer,” we’re informed — floats turd-like through the story, vaguely motivated by money and sex. Part of the trouble is that he’s already flush with both.

His editor, the “lazy, amusing Inigo Marcher,” ponies up a fat advance for Gabriel’s next masterpiece: a book about rivers called “Rivers.” “Going to be a huge success, laddie,” Marcher announces. “I can feel it in my cojones.”

As for sex, Gabriel is relentlessly serviced by his “incredibly, tumescently alluring” girlfriend, Lorraine. Because she waits tables and speaks in a coarse accent, Gabriel looks down on Lorraine in a way that turns him on: “Exotic, strange … Lorraine was terra incognita.”

But all their “energetic, inventive, always satisfying” bonking doesn’t stop Gabe from hitting on every femme fatale who prances across his path. These women hold Gabriel to low standards and therefore find him irresistible. “Very punctual, Gabriel. I’m impressed,” Faith purrs when he shows up on time to a meeting.

The stakes escalate to the level of global crisis. Bit players are cruelly killed. Boyd conveys these plot points in expository dialogue, insulating the narrative from any real sense of danger. Indeed, our hero suffers little more than a series of hangovers.

In the “Descent Into Hell” phase of the hero’s journey, when Thomas Fowler, for example, confronts dismembered bodies on the streets of Saigon, Gabriel takes a road trip through Poland, during which he must subsist entirely on candy, doughnuts and soda, and sleep in his car.

By this point, one suspects that the author is in on the joke. Gabriel is a moron coated in Teflon, and his invincibility can be read as a satire of the Cold War era, when entitled men meddled with impunity in the fates of nations. Like Sherman McCoy in “The Bonfire of the Vanities,” Gabe is the embodiment of a sick society: an antihero whom readers may love to hate.

A more satisfying satire might have concluded with K.G.B. agents thoroughly torturing Gabriel, only to discover that his pretty head contains nothing of interest. Instead, Boyd covers for Gabriel with an incongruously earnest subplot.

The cad is an insomniac, tormented by dreams of the fire that killed his mother.

These nightmares finally subside on the night he sleeps in his Polish rental car. Could this be transformation in Gabriel’s character? Not really.

As Gabriel’s quaint misadventures conclude, he remains adrift in his own ego, horny as a bonobo, and primed by Boyd to star in a sequel.

I do see a certain nostalgic appeal. This book recalls a simpler time for men like Gabriel Dax. As the world changes, many will prefer to look backward.