‘What is possible?’

“I think what was driving me was just, it was almost this perfect opportunity to see what Michael could do, just from an intellectual standpoint. What is possible?” said Bowman, who served as Phelps’ motivator, father figure, friend and partner over a 20-year coaching relationship. “It wasn’t so much that if he didn’t get eight gold medals, it would be a failure. It was, how far could he push the limits of what could be done at one swim meet?”

In fact, Bowman, who apologized last month after it was reported that he sent inappropriate texts to former Olympic swimmer Caroline Burckle in 2011, remained skeptical even after the 2004 Olympics in Athens, where Phelps won six gold and two bronze medals. He figured the vagaries of relays and late-week fatigue would always make eight gold medals unlikely.

He didn’t truly change his tune until the 2007 world championships, where Phelps set five world records in perhaps the most perfect meet of his career.

At that point, he was a flawless swimming machine, hugely gifted but also shaped by thousands of hours of detailed work at pools in Mount Washington and later at the University of Michigan.

“They were at my feet in every race,” Phelps said of his rivals.

He would come to hate swimming much of the time as he prepared for his fourth Olympics in London. And with that loss of athletic motivation, cracks in his deeper sense of self began to manifest.

But in the runup to Beijing, he was so consumed by his youthful ambitions that he pushed back the demons that would later chase him.

“I think just the thought of attempting something so challenging that no one else had ever done it in history, that kind of covered everything else up and allowed my mind to free up,” he said. “I didn’t really take in anything of what was going [on] outside. I was just so focused on what I was doing in the pool. That had to engulf every ounce of energy and time to prepare for