Former Nuggets coach George Karl took a series of personal shots at Carmelo Anthony in an upcoming memoir, claiming Anthony was “a conundrum,’’ a user, not a leader and unwilling to share “the spotlight’’ or play defense during their six years together.

Karl also took aim in “Furious George’’ at former Nuggets, and ex-Knicks, J.R. Smith and Kenyon Martin. He branded the trio of Anthony, Smith and Martin as “AAU babies’’ — akin to “the spoiled brats you see in junior golf and junior tennis.’’

Karl also referred to Smith’s entourage as “posse’’ — a racially loaded phrase that got Knicks president Phil Jackson in hot water when he used it regarding LeBron James’ managers.

Karl coached Anthony from January 2005 to February 2011, when Anthony’s trade demand was heeded. Karl’s memoir will be out in January. In a review copy obtained by The Post, Karl hammered Anthony more harshly than he ever had in the past.

“Carmelo was a true conundrum for me in the six years I had him,” Karl wrote. “He was the best offensive player I ever coached. He was also a user of people, addicted to the spotlight and very unhappy when he had to share it.

“He really lit my fuse with his low demand of himself on defense. He had no commitment to the hard, dirty work of stopping the other guy. My ideal — probably every coach’s ideal — is when your best player is also your leader. But since Carmelo only played hard on one side of the ball, he made it plain he couldn’t lead the Nuggets, even though he said he wanted to. Coaching him meant working around his defense and compensating for his attitude.”

Karl also wrote: “The volume of questions about Carmelo eventually wore me down. Sometimes I got so sick of talking about him that I’d just throw up my hands and say: ‘I don’t know what he is and I don’t care.’ ”

Karl wrote Anthony and Martin not having fathers in their lives became a detriment to their personalities.

“Kenyon and Carmelo carried two big burdens: all that money and no father to show them how to act like a man,” Karl wrote.

Karl wrote Anthony “was such a talented kid,’’ he could’ve “become the best defender at his position in the NBA.’’

Referring to one reason Anthony sought greener pastures, Karl wrote they had “a little conflict bubbling.”

“I want as much effort on defense — maybe more — as on offense,” Karl penned. “That was never going to happen with Melo, whose amazing ability to score with the ball made him a star but didn’t make him a winner. Which I pointed out to him. Which he didn’t like.”

He also dredged up old stuff, referencing Anthony getting a DUI in 2008, getting “busted at the airport for having a bag of weed in his backpack’’ in 2004, getting “in a bar fight” and his “infamous brawl’’ versus the Knicks in 2006. Karl also alleges Anthony “refused to go back into the last minute or two in a game on the road against the Pistons’’ — an incident that went unreported.

Karl called Anthony’s trade to the Knicks “a sweet release for the coach and the team, like popping a blister.’’

“We won this trade, definitely,’’ Karl wrote, referring to the Nuggets swapping Anthony and Chauncey Billups to the Knicks for Danilo Gallinari, Wilson Chandler, Raymond Felton, Timofey Mozgov and draft picks.

Regarding Smith, Karl wrote that Smith’s father, Earl Sr., “urged his son to shoot the ball and keep shooting it from the very moment I put him in the game.’’

Karl wrote Smith carried “a huge sense of entitlement, a distracting posse, his eye always on the next contract and some really unbelievable shot selection.

“When we traded J.R. in 2011, I was disappointed that I hadn’t helped a clearly talented player advance his game more.’’

After the Anthony trade in 2011, Karl took some shots at Anthony for his defensive indifference, to which Anthony responded on Twitter: “When the grass is cut, the snakes will show.’’ In recent years, Karl has praised Anthony for his evolving game.