From the New York Daily News’ Michael O’Keefe.

You’ve never seen Jose Canseco like this: huddled in a bathroom stall at the Oakland Coliseum, jabbing a hypodermic needle into Mark McGwire’s bare behind.

Or McGwire and a young Jason Giambi heading into the men’s room to inject each other with the anabolic steroids that would turn them from lanky lads into musclebound behemoths.

Bad boy Canseco alleges those and other mind-bending scenes in a soon-to-be released tome that is already shaking the world of baseball.

In “Juiced: Wild Times, Rampant ‘Roids, Smash Hits and How Baseball Got Big,” Canseco claims he personally injected some of the biggest names in baseball – including All-Stars Rafael Palmeiro, Juan Gonzalez and Ivan Rodriguez, among others – with performance-enhancing drugs.

But if the book is a confessional, Canseco isn’t seeking redemption. “Juiced” is a love letter to the clear liquids that turned him from struggling skinny prospect to one of the biggest names in the game.

The implausibly buff slugger admitted to doping several years ago, but in the book he claims he was almost solely responsible for spreading steroids throughout the game in the 1990s. The book, which is still being edited, is scheduled for release Feb. 21.

Canseco, who played for seven big league teams in a 17-year career – including a brief stint with the Yankees in 2000 – expresses no regrets in the book. In fact, he predicts steroids and human growth hormone will eventually be decriminalized and help people lead longer, healthier and sexier lives.

Giambi’s agent, Arn Tellem, questioned Canseco’s credibility:

“This book, which attacks baseball and many of its players, was written to make a quick buck by a guy desperate for attention, who has appeared on more police blotters then line-up cards in recent years, has no runs, no hits and is all errors,” Tellem told the Daily News.

Among his many bombshells, Canseco claims:

* – McGwire introduced Giambi to performance-enhancing drugs and the three of them used to shoot steroids together. Canseco says players on the A’s talked openly about injecting in the bathroom stalls, and the clubhouse was an abuser’s paradise.

* – During the great home run race of 1998, a reporter’s accidental discovery of androstenedione in McGwire’s locker, may not have been an accident. Canseco says he believes McGwire put the bottle of the steroid “pre-cursor” in his locker so it would be found, thus creating a smokescreen for his extensive use of illegal steroids. Andro, recently criminalized, was legal at the time.

* – President Bush, who was the Rangers’ general managing partner in the early ’90s, must have known that some of his players were using steroids but chose not to address the issue.

Reaction was swift from the accused. McGwire, Canseco’s biggest target who has long denied steroid use, said in a statement: “I have always told the truth and I am saddened that I continue to face this line of questioning. With regard to this book, I am reserving comment until I have the chance to review its contents myself.”

Added Tellem: “It only confirms what the great baseball writer Peter Gammons said when he called Jose Canseco one of the three greatest wastes of baseball talent between 1980 and 2000.”