At first glance, Matthew Quick's latest novel appears to be cut from the same cloth as his celebrated 2008 debut, "The Silver Linings Playbook." Each has as its narrator an emotionally scarred man, one who has lost a woman and spent time in psychiatric care, and is now sifting traumatic memories and navigating present upheavals in search of answers and closure.

There, however, the similarities end. "The Reason You're Alive" soon develops into an entirely original work, at once poignant and uproarious, thanks in no small part to the uncensored opinions and audacious exploits of its compelling protagonist.

He is 68-year-old David Granger, a Vietnam veteran and American patriot. When he crashes his BMW, surgeons discover a brain tumor that he ascribes to Agent Orange exposure. Fortunately, the scalpel "tickled" some dormant personal recollections.

Granger's narrative — and Quick's novel — takes the form of a candid report in which he relates all that has happened to him in the past 50 years, including overdue attempts to right some wrongs.

His testimony begins with a tour of duty that incorporates jungle killing sprees, unlikely alliances and stockpiled gold. After the war Granger winds up in "a military loony bin" in Kansas, then starts a family and builds a career as a banker in Philadelphia.

Granger's past is colorful, at times lurid, but his current situation proves more absorbing. He hatches a grand plan with billionaire pal Frank, acts as matchmaker for best friend Sue and arranges a showdown with an American Indian nemesis he calls Clayton Fire Bear.

Best of all, though, is his fraught relationship with Hank, his gun-hating, Barack Obama-loving "civilian son."

This is a novel that thrums with energy, and the source of it is its foul-mouthed, big-hearted, larger-than-life narrator. Granger, a "dangerous right-wing grandpa," is an unstoppable force whose presence fills each page and dominates every scene. His thoughts are riffs, his speeches salvos. He fulminates against liberals, lawyers and uncaring Uncle Sam; he scoffs at "heart-healthy" food, his insufferable Dutch daughter-in-law and "morons" of all stripes.

For Hank, his parent is "the most offensive and the absolute most politically incorrect person I have ever met." But while Granger is outspoken, he is no bigot. The novel's riotous humor comes from his misunderstandings and generalizations, his gauche moves and skewed views. Gandhi was "India's most famous pervert." Doctors are only ever "pill pushers, needle pokers, or people cutters." Granger assures us he would gladly go into battle with his two gay friends — even on gay pride day, when they wear rainbow colors, "which is not good camouflage."

When Granger veers close to caricature, Quick tones down his antihero's brashness and reveals a tender side — doting on his granddaughter, looking after his troubled wife, mourning those who have "bought the bullet."

The end result is a vibrant and compassionate tale of a complex man finding his way in a divided America.

Malcolm Forbes has written for the Times Literary Supplement, the Economist and the Daily Beast. He lives in Edinburgh, Scotland.

The Reason You're Alive
By: Matthew Quick.
Publisher: Harper, 226 pages, $25.99.