Four years is a long time. It’s a long time in almost any avenue of life. But in international soccer? It’s an eternity. Which is why casual fans tuning into the sport for World Cups and World Cups only have a lot of catching up to do.

If you’re reading this, chances are you were one of millions captivated by the U.S. women’s national team in 2015. By the personalities and the patriotism. By the fortitude under pressure and the flair. By the world champions.

And chances are that you, just like the USWNT, are back for more.

But you might not have tracked every step, every kick, every lineup change or every controversy over the past three years and 10 months. So, to help you get caught up, we’ve compiled a handy guide to the U.S. women’s national team in 2019 – recapping the World Cup interim, introducing the new faces, re-introducing the only ones in new places, and much more.

The USWNT’s past four years in 150 words

After a parade, a White House visit and a victory tour, a 2016 Olympic quarterfinal loss to Sweden stoked a cycle of rejuvenation. Hope Solo was unceremoniously axed. Longtime stars like Abby Wambach and Christie Rampone had retired. Their former understudies have meshed with up-and-comers to form the USWNT’s 2019 core.

That formation, though, was an arduous process. Head coach Jill Ellis called up 61 different players since Rio 2016. She piloted new tactics and systems. The result was a three-loss 2017, and reportedly a meeting between veteran players and then-U.S. Soccer president Sunil Gulati to voice concerns about Ellis.

There has also been off-field friction – lawsuits, wage discrimination complaints, contentious collective bargaining.

But following the third 2017 defeat, the U.S. women went 28 games unbeaten – 25 wins, three draws. They looked World Cup-ready last fall. And they may even be better than their 2015 selves.

Is the U.S. still the world’s best?

Yes. The U.S. is by no means a sure thing to repeat. In fact, a repeat isn’t likely. The Americans are, however, either the betting favorite or one of two joint-favorites. And their challenger for the pre-tournament throne, France, is only neck-and-neck thanks to its host-country bump.

All that might sound paradoxical, but it’s simply the nature of quadrennial 24-team tournaments. “Betting favorites” have less than a 25 percent chance at confetti and champagne on July 7. Soccer, especially when played in win-or-go-home knockout competitions, is a fickle sport.

The U.S., however, has more depth, more athletic prowess, and more attacking verve than any other World Cup participant.

What are the USWNT’s strengths?

Attacking depth and sheer athleticism.

The U.S. has no fewer than six forwards who would start and star on almost any team in the world. Its left back is a natural winger and former golden boot winner in the sport’s most competitive club league, the NWSL. All three first-choice midfielders contribute in the final third.

[More: Meet the 23 U.S. players going to the World Cup]

And the Americans still have more speed and power than any of their counterparts. They’re dominant on set pieces. They consistently win individual battles all over the pitch, and thrive when a game’s structure becomes splintered.

They have a few weaknesses, but the strengths very often render them unnoticeable or inconsequential.

What are the USWNT’s weaknesses?

Individually, goalkeeper is now the problem position. (More on that in a bit.) Collectively, the problem is a penchant for leaving that goalkeeper – and the defense in front of her – exposed.

The U.S. plays an attacking 4-3-3 with attacking fullbacks, two attacking midfielders, and a “holding” midfielder who rampages all over – in other words, who doesn’t really “hold.” That leaves a center back pairing that isn’t quite as mobile as 2015’s unsheltered and vulnerable to counterattacks.

Which 2015 heroes are still around?

Of the 23 players with winners medals from 2015, 12 are back for another go. And 15 of the 18 from the 2016 Olympics are among this year’s 23. There’s a lot of experience – 1,841 national team appearances, to be exact. There’s been relatively little turnover.

The names you’ll remember are Alex Morgan, Megan Rapinoe, Tobin Heath and Becky Sauerbrunn. They’ll be starting in the same positions (striker, winger, winger and center back) as four years ago. The fifth starting lineup holdover is Julie Ertz – formerly Johnston, before marrying Philadelphia Eagles tight end Zach in 2017. A defender in 2015, she’s now the defensive midfield destroyer.

Among other 2015 starters, attacker Carli Lloyd, midfielder Morgan Brian and fullback Ali Krieger are now reserves. (Conversely, defender Kelley O’Hara and goalkeeper Alyssa Naeher, reserves in 2015, are now starters. Forward Christen Press is still great, but still stuck behind others on the depth chart.)

[More USWNT coverage: Carli Lloyd on her new role]

The three who are no longer in the picture are Solo, left back Meghan Klingenberg and midfielder Lauren Holiday. They’ve given way to either rising stars or question marks.

Who are the new stars?

If you’ve been completely tuned out between World Cups, the six names to learn are Lindsey Horan, Crystal Dunn, Rose Lavelle, Abby Dahlkemper, Alyssa Naeher and Mallory Pugh.

Five of the six are starters. Horan, 24, the 2018 NWSL MVP, is a brilliant all-around midfielder. Dunn, 26, is the aforementioned forward-turned-left back. Lavelle, 23, is a delightful playmaker who’ll be the most advanced of the midfield three. Dahlkemper, 25, will start at center back.

Pugh, 21, started Olympic games as an 18-year-old, and in all likelihood will be in many World Cup 11s as her career progresses. She’s the brightest prospect in the U.S. player pool. In fact, calling her a “prospect” doesn’t do her present-day ability justice. But for now, she’s the one of those six who’ll go to France as a bench option.

Then there’s Naeher, who’s 31 and doesn’t exactly fit the “rising star” description. But she’ll have a major role to play this summer.

The Hope Solo fallout and replacement

When Solo had her contract terminated after calling the Swedish side that had toppled Team USA “cowards” in 2016, there was no clear replacement waiting in the wings. Naeher and Ashlyn Harris competed for the starting gig. Naeher won it, and has been the clear No. 1 for a while now. No other keeper has started consecutive USWNT games since late 2016.

But, while she’s been solid at club level, she’s been shaky on the international scene. Solo was the best goalkeeper in the world. Naeher is not, and will therefore be under pressure the first time she falters on the World Cup stage.

What went wrong at the 2016 Olympics?

First, we should caution against gleaning too much from 2016. That was three years ago. The U.S. didn’t even lose a game. It was ousted on penalties. As we hinted earlier: Sometimes in soccer, randomness reigns.

But the U.S. did have real problems building through midfield and creating chances against low blocks. Rapinoe, coming off ACL surgery in the winter, wasn’t healthy. Without her, imagination ebbed, and the U.S. had few answers for parked busses.

In the years since, however, they’ve found some.

The 2015 —> 2019 trajectory

The U.S. has not gone World Cup to World Cup as the undisputed queens of women’s soccer. There have been bumps, obstacles, upheaval – probably more than we realize.

After the failure in Brazil, Ellis went into experimentation mode, broadening the player pool. Per U.S. Soccer records, between Rio 2016 and France 2019, 30 players were called into their first national team camps. Twenty debuted.

The results, initially, were troublesome. The U.S. went 1-2 with a minus-3 goal differential at the 2017 SheBelieves Cup, losing to England and France. It eked out a couple 1-0 wins in Europe in June, but then fell to Australia to open the 2017 Tournament of Nations. The product seemed stale, the tactics sometimes incoherent.

But over the 12 months that followed, the U.S. found its identity. In its first match post-Tournament of Nations, Ellis rolled out a 4-3-3 with Naeher in goal, Sauerbrunn and Dahlkemper in the center of defense, Ertz as the defensive midfielder, Horan as a more attacking mid, Morgan up top and Rapinoe to her left. That’s essentially been the foundation since. The U.S. rattled off 28 unbeaten, defeating Brazil, Japan, Canada, Germany and England along the way. The streak finally ended this past January in France, but it remains representative of a team on a roll.

Who is the USWNT’s top World Cup competition?

Look no further than the last two teams to beat the Yanks: France and Australia. With the caveat that the French beat a USWNT sans five starters, and the Aussies’ triumph was almost two years ago. But each has a 1-through-11 that can measure up to the Americans. The U.S. is 1(W)-3(L)-2(D) against those two opponents since March 2017.

Among the other contenders are Germany, England, the Netherlands, Japan and Canada. But the U.S., if all goes to plan, is on a quarterfinal collision course with France. They’d meet in Paris on June 28. That’s the date circled on calendars.

When and how to watch the World Cup

The World Cup kicks off June 7 with France-South Korea at 3 p.m. ET on Fox Sports 1. The U.S. begins its Group F campaign four days later, on June 11. Here’s the USWNT’s schedule:

• June 11: U.S. vs. Thailand, 3 p.m. ET, Fox

• June 16: U.S. vs. Chile, Noon ET, Fox

• June 20: U.S. vs. Sweden, 3 p.m. ET, Fox

The knockout round begins two days later. The full schedule is here. All games will be broadcast on either Fox or Fox Sports 1 in English, and either Telemundo or Universo in Spanish.

How to follow the USWNT in the meantime

In the meantime, there are countless ways to get your soccer fix. Here’s how to prepare for June, in three steps:

1. Watch the USWNT’s send-off friendlies: Against South Africa on May 12 (4:30 ET, Fox), New Zealand on May 16 (8 ET, ESPN2), and Mexico on May 26 (Noon ET, ESPN).

2. Read up on the roster, and follow along with all of Yahoo Sports’ buildup coverage. Our Women’s World Cup hub will house all of our preview content over the coming month.

3. Watch some of the sport’s best non-World Cup players in the NWSL. You can stream every game live on Yahoo Sports.

And with that, our month of comprehensive coverage, which will lead into a month of world-class soccer, is underway. Glad to have you along for the ride.

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Henry Bushnell is a features writer for Yahoo Sports. Have a tip? Question? Comment? Email him at henrydbushnell@gmail.com, or follow him on Twitter @HenryBushnell, and on Facebook.