“A thinker” is how his coach, Gregg Troy, describes him.

Dressel is an avid reader. His infrequent posts on social media are often quoted from whatever book has his attention at the moment.

“I can get the physical exercise done with practice and staying in shape,” he said. “But you’ve got to sharpen the mental side. I like to learn.”

Recently, he read Ryan Holiday’s book “The Obstacle Is the Way: The Timeless Art of Turning Trials into Triumph.”

“ The good thing about true perseverance is that it can’t be stopped by anything besides death,» Dressel tweeted.

Another recommendation from Dressel’s book club is “The Wright Brothers,” a 2015 work by historian David McCullough chronicling the life and times of aviation pioneers Orville and Wilbur Wright.

Dressel was taken with these lines: «All were extremely proud of the brothers, not because that was the fashion of the moment, but because of their grit, persistence, and their loyalty to conviction. Above all because of their sterling American quality of compelling success.”

That’s a quality Dressell knows something about.

At the 2017 FINA world championships in Budapest, he joined Phelps and Mark Spitz as the only swimmers to win seven gold medals at a major international meet.

This summer in South Korea, Dressel picked off six golds and two silvers — making him and Phelps the only swimmers to claim eight medals at either the Olympics or the worlds. Most impressively, Dressel won three titles in a single night.

«He’s such a dynamic swimmer,» said Bob Bowman, who was Phelps’ coach throughout his career and now leads the swimming program at Arizona State. “The way he jumps off the block. The race is over when he hits the water. He’s so strong. I think of power when I see him swim.»

Now, as Tokyo approaches, Dressel is 23 years old.

The same age as Phelps heading into the 2008 Summer Games.

But Dressel quickly shoots down any thought of making a run at Phelps’ most iconic record — those eight gold medals at the Beijing Olympics.

Two of Dressel’s eight events in Gwangju (50-meter butterfly and 4×100 freestyle relay) aren’t on the Olympic program.

He’s pondering whether to swim the 200 free at the U.S. trials, in hopes of putting up a time that would earn consideration for a spot on the 4×200 free relay. But it looks like seven events is the absolute ceiling he’ll consider for Tokyo.

Dressel shrugs off speculation that he might attempt the 200 individual medley, saying it just doesn’t work out schedule-wise.

So Phelps’ record is safe.

Not that it’s ever been on Dressel’s radar.

“It’s not about Michael for me,» he said. “It never has been.”

The third of four children, Dressel grew up in Green Cove Springs, Florida, a community just south of Jacksonville along the St. Johns River. He played a variety of sports, including football, track and soccer, but swimming was his destiny.

“To put it simply, this is what I’m supposed to be doing,” he said “I don’t know if it chose me or I chose it. But I couldn’t walk away from it, even at the points where I didn’t enjoy it.”

There were certainly times when he struggled to find joy in the sport — most notably during his senior year of high school, when he was one of the nation’s top swimming prospects but shockingly decided to drop out for about six months.

Dressel clams up when asked about that time in his life.

“I genuinely missed it,” is about all he’ll say. “I’ve sort of beat around the bush with my answers. Maybe one day I’ll actually come out and give the full story. But right now, I’m not ready.”

He returned to swimming, of course, with a scholarship to compete right down the road at the University of Florida. That’s where he hooked up with Troy, the school’s longtime coach, and began a partnership that would produce some staggering returns.

Dressel earned his first Olympic berth in 2016 and led off the gold medal-winning 4×100 free relay team that also included Phelps, who retired for good after Rio with 23 gold medals from his brilliant career.

Dressel earned a second gold by swimming the preliminaries of the 4×100 medley relay. In his only individual event, he finished sixth in the 100 free.

The last two world championships gave Dressel a chance to expand his horizons.

He’s gotten a taste of what it means to be one of the faces of U.S. swimming.

“He dealt with the pressure of being the star,” Troy said. “Now, I think, he’s kind of the complete package.»

While Dressel doesn’t seem to care much about medals, there is one possession that he’s never without at the biggest meets — a blue and black bandanna imprinted with images of cows.

It belonged to Claire McCool, one of his math teachers at Clay High School. She died in 2017 after a two-year battle with breast cancer.

The bandanna was one of several she wore while undergoing treatment. Her children each got one. Her husband, Mike, wanted Dressel to have one, too.

“It’s just something special that I get to hold on to that represents her, something physical,” he said. “I needed something physical. I’m glad I got the bandanna.”

But, like that time when he quit swimming, Dressel prefers to keep his bond with McCool close to the vest.

“I’d rather not speak too long on Mrs. McCool, if that’s all right,” he said. “Her classroom was a safe haven. I can’t tell you how many classes I skipped because I was hanging out in her classroom.”

While Dressel’s Wikipedia page says he graduated from Florida, he conceded that he’s still about 15 hours short of completing his degree in resources and conservation.

As his swimming career ramped up, he wasn’t able to finish his last few classes.

That gap in his resume gnaws at him.

“I want to have a diploma to hang on my wall,» he said. “Even if I don’t use it, I can say I graduated from UF.”

He’s got far too much on his plate at the moment to take any classes, though the trappings of stardom require Dressel to do things that aren’t exactly in his comfort zone.

Troy, whose stable of swimmers includes attention-craving Ryan Lochte, noted that Dressel takes a totally different approach away from the pool.

“Ryan loves the publicity and looks forward to it,” Troy said. “Caeleb could do without it.”

When Dressel is required to do a whirlwind promotional tour on behalf of a sponsor, like the one last month for Toyota ahead of the U.S. winter nationals in Atlanta, it’s very apparent he would rather be somewhere else.

“I don’t know if you’ll really get to know me unless you’re close to me,” he said. “If it was up to me, it would be me, Coach Troy and the water.”

Yet Dressel recognizes this comes with the territory when you’re getting mentioned in the same breath as swimmers such as Phelps and Spitz.

The spotlight in Tokyo will be bright, that’s for sure.

But Dressel plans to keep his head down. He’ll be focused on those black lines at the bottom of the pool.

That’s when he feels most at peace.

“I’m not doing this for money, I’m not doing this for fame,” Dressel said. “For me, it’s how far can I push this? How fast can I go?»