In the early 1960s, a family of Cuban refugees escaped to suburban New York, where they found a home in the middle-class Long Island neighborhood where author Nelson DeMille grew up. The parents, who were very bitter over losing everything, first piqued DeMille’s interest in Cuba’s police state. “I knew there was a story there,” he says. But it wasn’t until nearly three decades later, when he visited Cuba for the first time, that a novel about the island began to take shape.

DeMille’s 20th book and his first with Simon & Schuster, The Cuban Affair (Sept.) puts this troubled country in the spotlight. Daniel “Mac” MacCormick, a U.S. Army vet who completed two Afghanistan tours, finds a new life as a fishing boat captain in Key West, Fla. His bland, everyday charters are buoyed by covert adventure when he is asked to make the journey to Cuba with an enigmatic exile and a young woman to uncover a stash of money hidden by an émigré from Castro’s revolution.

DeMille set out to go beyond the romantic aura of pre-1959 vintage cars, cigars, and rum cocktails and delve deeper into the country’s complexities. In October 2015, he and his wife spent 11 days exploring Cuba. With him were his childhood friends who, through a connection to former Secretary of State John Kerry, orchestrated a meeting for all of them with Ambassador Jeffrey DeLaurentis at the newly opened American Embassy in Havana, one of the highlights of DeMille’s sojourn.

DeMille observed the ravages of an almost 60-year Communist reign up close. “First impressions color perceptions, and for me it felt like the Caribbean with a layer of police presence,” he says. “Hot and sunny, but with a Soviet pall. It’s a primitive economy that neglects infrastructure. People make $20 a month, and there’s a ration book. This generates a black market, but even then you can’t show your wealth. It’s true communism: everybody has nothing.”

Throughout his trip, DeMille met numerous Cubans who were hungry for positive change; others were satisfied with the status quo. This sharp divide of determination and optimism versus feelings of isolation and resentment is interwoven in Mac’s own clandestine mission, opening the main character’s eyes as much as DeMille’s.

Despite the poverty and crumbling buildings, DeMille was inspired by hopeful changes like the growing number of legal, private restaurants, as well as the lively cultural scene, teeming with quality music, dance, and visual arts. “I saw people on the promenade singing and dancing and throwing off their troubles of the day. It’s sundown freedom. Havana after dark makes America look like a convent,” he says.

Today, 10 a.m. Nelson DeMille will sign at the Simon & Schuster booth (1420, 1421).