Don Winslow is obsessed, and he knows it.

“People refer to this as the ‘Mexican drug problem’ and it’s NOT the Mexican drug problem. It’s the American drug problem. It’s the European drug problem,” the crime novelist says during a recent interview at the Landmark Tavern in Hell’s Kitchen, where he’s eating a late breakfast and discussing the events that inspired his new novel, “The Cartel.”

“We spend billions of dollars buying these drugs at the same time we spend billions of dollars a year trying to keep them from coming in. It’s that conflict, that schizophrenia, it’s that insanity that not only created the cartels but keeps them in business.”

The 61-year-old Winslow, bald and dark-eyed with a deliberate, focused speaking style, has become an unintentional expert on a subject that sickens him. Admittedly prone to “rant” once he gets started, he will invoke everything from philosophy books to World War II as he explains the long history of drugs in this hemisphere and how the U.S. got caught up in a conflict it doesn’t know how to stop.

In 2005, he published the 500-page “The Power of the Dog,” his brutal and acclaimed saga about the drug war and the rare honest man trying to end it — a maverick DEA agent named Art Keller. Convinced, like Keller, the story was told, Winslow moved on to other projects, including Oliver Stone’s adaptation of his novel “Savages.” But he never stopped keeping an eye on the latest in Mexico and was horrified as the casualties and the cruelties only accumulated. More than 100,000 people have been killed because of the wars among the drug cartels, according to some studies.

“I started reading again and watching again and talking to people, and I think for probably a year or more denying to myself and everybody else that I was going to do that book,” he says. “The more I read the angrier I got.”

Blurbed by James Ellroy as the “‘War and Peace’ of dope war books,” the 600-page “The Cartel,” like “Power of the Dog,” is an intricately detailed narrative of the cartel life — where they live, the cars they drive, the clothes they wear. Winslow’s editor, Alfred A. Knopf publisher Sonny Mehta, said at times the author seemed so immersed in the world of his book he worried that Winslow might have “crossed some lines” and put himself in danger.

Winslow’s research included talking to former government agents and sources connected enough to the cartels to know how they work, providing they’re willing to say how the cartels work.

“Some people were like, ‘Yeah, cool,’” Winslow said. “Other people were like, ‘I don’t know, not so sure.’ And it’s a matter of getting known a little bit. I always call it the ‘furniture process.’ It’s a matter of becoming furniture. You’re in a room, in a bar, whatever, and you sit there. ... Then you start to pick up what I like to call the ‘music of it.’”

The author of more than a dozen books, Winslow has been a student of crime since growing up in the Rhode Island village of Perryville, when rival gangs from Boston and Providence battled. Hell’s Kitchen, the midtown Manhattan neighborhood that once well earned its nickname, brings its own history.

He was a private investigator and security officer in New York in the 1970s and ’80s and sets part of “The Power of the Dog” in Hell’s Kitchen. He has memories of convincing a German tourist that it might not be a good idea to photograph a crack deal, of being startled by gunshots late at night while depositing a movie theater’s money in a bank, only to realize that it was July 3 and he was hearing fireworks.

He remembers another night, hanging out with law enforcement officials at a nearby tavern.

“It’s about 1:30-2 (a.m.) in the morning and some poor kid comes to rob this place, and he must have been the least informed armed robber in the city,” Winslow says.

“And this kid comes in with a gun pulled, ‘This is a stickup!’ And there are five cops, five plainclothes cops, all Irish. And they all laughed. The bartender laughed. Everybody in the place laughed.”

The drug war is local news for Winslow, who with his wife, Jean, lives in a rural Southern California community close enough to Mexico to see Border Patrol agents race across his property. He decided to write “Power of the Dog” after reading a newspaper article describing the murder of 19 people, lined up against a wall and machine-gunned, in a Mexican town he had visited.

“Before that I had never been interested in the war on drugs, or the drug trade,” Winslow says.

Keller notes that violence in Mexico seems to have subsided in the past few years, but worries about a recent increase in shootings in Tijuana. Perhaps Keller will have to return and take on the drug lords one more time?

“He’s not coming back,” Winslow says.

Really?

“This time I mean it.”