The greatest season in major league history, according to Baseball-Reference.com's wins above replacement, was Babe Ruth's 1923. That's probably not the Babe Ruth season you're thinking of: not the one in which he became a two-way star (8.0 WAR) or the one in which he outhomered 10 teams (9.9) or the one in which he nearly doubled the single-season home run record (11.9) or the one in which he set the single-season home run mark that would last until Roger Maris (12.4) or the one in which he set a record for total bases that still stands today (12.9). That last one, that's the second-greatest season in major league history, according to WAR, and the 60 homers were the fourth-greatest. Ruth seasons also rank seventh, 10th and 12th among all offensive seasons.

But the 1923 season is the year Ruth did everything. He hit .393, the closest he ever came to .400. He drew 170 walks, the most of his career and a record that stood for almost 80 years. His league-leading 41 homers were just the 10th-highest total of his career, but he set a career high for doubles, matched a career high for steals, set a career high with a .545 on-base percentage and tripled 13 times. He threw out 20 baserunners from the outfield and -- to the best of our ability to say things such as this 95 years after the fact -- he had the best defensive season of his career. He stayed healthy and unsuspended, and he had a career-high 697 plate appearances and a career-high 1,335 innings in the outfield. None of that smashes you over the head like "outhomered 10 teams" does, but it was the perfect season for an everything stat like WAR: It showed the cumulative value of disparate excellence. Ruth won the MVP award, a laughable understatement. He was the most valuable player ever. He was worth 14.1 wins above replacement.

On Sunday, the Angels played their 40th game, the closest thing to a quarter mark for the season. Mike Trout started the game on the bench -- his first day off of the season -- and finished it with 3.51 WAR. The game's best player was on pace to produce 14.2 wins above replacement. It's almost unimaginable -- nobody has cracked 12 WAR in a half-century, and no active player has ever WAR'd higher than 2016 Trout's 10.5 -- but it's time to take seriously the possibility that we're watching the greatest season of all time. Also, considering how relatively quiet it has been, it's time also to wonder: How?

There are two things to know. The first is this: Between April 8, when after 10 games of the season, Baseball-Reference tallied up 2018 WAR for the first time, and Sunday, Trout played 30 games. In 25 of those games, he had a positive WAR. This isn't normal in baseball -- not even for superstars. Trout doesn't homer every day; he doesn't even get a hit every day. But almost every day, he finds a way to add value some way or another.

The second thing to know is this: There is no area of WAR's calculations in which Trout isn't sensational right now, which helps explain the first thing to know. WAR involves dozens of calculations, but it can be summed up simply like this: It's a player's hitting value (batting runs) added to his defensive value (defensive runs saved compared to others at the position, plus adjustments for the difficulty of his position) added to his baserunning value (baserunning runs) added to, as the final pinch of detail, his value added by not hitting into double plays. These are Trout's paces in each of the four through Sunday and where those paces would have ranked among all major leaguers in 2017:

Trout was on pace to produce 85 batting runs. Last year, Aaron Judge led the majors with 61 batting runs. Nobody has produced 85 or more batting runs since Barry Bonds in 2004. The most this decade was 71 by Bryce Harper.

He was on pace to produce 8.1 baserunning runs. Last year, that would have ranked third in baseball, behind Byron Buxton (9.1) and Mookie Betts (9.0).

He was on pace to produce 20.3 defensive runs saved, at a premium position, for a total defensive WAR of about 2.7. Last year, that would have ranked fourth among all defenders at all positions, behind Andrelton Simmons, Buxton and catcher Tucker Barnhart.

Even his double-play rate was adding value. After grounding into two early in the season, Trout grounded into just one more over his next 30 opportunities (runner on first, fewer than two outs), about one-third of the leaguewide average in such situations. He was on pace to add about 1.5 runs of value by avoiding double plays, which would have been 28th-best in baseball last season and ninth among all right-handed batters.

If all we knew was what Trout's hitting stats looked like, we'd be blown away. He's slugging .616 in a pitchers' park and on pace to hit 45 homers, steal 30 bases and score 128 runs. That's Bonds' 1993 season (9.9 WAR) or Chipper Jones' 1999 (6.9) or Larry Walker's 1997 (9.8), all of them MVP-winning seasons. But where Trout stands out is on the days when his hitting stats get worse, on the 0-fors. He has seven this year in which his WAR went up:

April 11: 0-for-2 with a sacrifice fly. He also was hit by a pitch and drew a walk, though. Trout is on pace to draw 143 walks, which would match Joey Votto's 2015 season for the most since Bonds. It's not that pitchers are terrified of him -- Trout has only four intentional walks, and he's seeing more pitches in the strike zone this year (49 percent of pitches) than he did last year and more than the league average. Rather, it's that he has developed perhaps the best eye in baseball. Only two batters have chased fewer pitches out of the strike zone than Trout has this season.

April 29: 0-for-2. He also drew two walks and reached on an error. Boring day with a .500 on-base percentage.

May 1: 0-for-1, four walks. Beside almost never swinging at pitches out of the zone, Trout this year has had an uncanny ability to avoid contact when he does chase, so that he isn't losing entire at-bats by making bad contact on dumb pitches. On pitches in the zone, he has a 90th-percentile contact rate. On pitches outside the zone, he has a 30th-percentile contact rate.

When Trout was facing Brad Brach with a tie game in the ninth inning May 1, and Brach threw him a 1-1 splitter a couple of inches below the bottom of the zone -- a pitch called a strike just 3 percent of the time -- Trout took a cut at it. Brach was looking for a double play, and he got the swing he wanted, but Trout whiffed. It's a weird sport in which missing a pitch by a little is worse than missing it by a lot, but in this case, Trout's whiff merely put him behind in the count. He worked that 1-2 count into a walk, and the Angels walked off on a Justin Upton single a couple of minutes later.

May 8: 0-for-3. In the sixth inning, with two men on, the Rockies' Tony Wolters hit a line drive 103 mph into center field. Based on the elevation and velocity, it's a hit 78 percent of the time, according to Statcast data, but Trout was well-positioned, got a good break, caught it running in and doubled up Gerardo Parra at second base. It doesn't look extraordinary:

But that has been typical of Trout's defense this season. He isn't routinely stealing home runs like he did as a rookie, but according to Sports Info Solutions, he has been well-positioned to take away hits such as that one from Wolters. That catch was worth a little more than half a run, according to SIS, which provides the defensive data for WAR. Two of Trout's most valuable catches of the year -- a line drive hit by Francisco Lindor on April 2 and a liner hit by Erik Gonzalez the next night -- are testaments to the Angels' positioning more than Trout's exceptional range.

Of course, the range is there, too:

May 10: 0-for-2. He also drew a walk, and he was hit by a pitch. Boring day with a .500 on-base percentage.

May 12: 0-for-2. Probably my favorite hitless Trout game of the season so far. He drew four walks, but the sequence I love is in the 11th inning. With Zack Cozart on first as the potential winning run, Trout grounded it to the third baseman, who threw out Cozart. That's a failure. But Trout's power had the third baseman playing deep against him, which, combined with Trout's speed, made it impossible for the Twins to turn the double play. Trout beat the throw to first. That's a tiny, tiny, tiny bump to his WAR.

So then Trout was on base. On the second pitch to Upton, he stole second. That was Trout's eighth steal of the year, and he has yet to be caught. Indeed, through the first quarter of the season, Trout hadn't made any outs on the bases. A couple of years ago, it seemed clear that his once-elite speed had become merely very good speed, as he had gotten older, gotten a little thicker, settled into the playing style of a more power-based superstar. Unexpectedly, though, the elite speed came back. According to Statcast's data, Trout's sprint speed in 2016 was 28.9 feet per second, the 48th-fastest in baseball. Fast! But this year he's running 29.4 feet per second, the 14th-fastest runner in baseball, just ahead of Dee Gordon. And so, on the second pitch to Upton, he stole second base.

That stolen base changed everything. When Upton flied out to right, Trout went to third as the winning run in the bottom of the 11th inning. Any single, or even wild pitch, would win it, so Twins manager Paul Molitor elected to intentionally walk Albert Pujols and Simmons and face Jefry Marte. Those walks will add to the WARs of Pujols and Simmons, respectively, but Trout made them happen by getting into scoring position.

And then, after Marte grounded out, and the Angels gave up two runs in the top of the 12th, the Angels batted one last time. Ian Kinsler walked, Kole Calhoun grounded into a double play, Rene Rivera walked, and Cozart flied out to end the game with Trout on deck. If not for that double play or that fly out, Trout very well might have batted as the winning run, the best hitter in baseball getting the chance to win it, the best-case scenario for the Angels. The reason he nearly got that chance is one inning earlier, Paul Molitor intentionally walked Albert Pujols and Andrelton Simmons, turning the lineup over more quickly, getting to Trout sooner, all because Trout beat that potential double play, stole second base and went to third on a Justin Upton fly out.

May 13: 0-for-1. Trout had the day off. He pinch hit in the seventh and struck out, stayed in the game for defense, and in the ninth inning, he fielded a ball off the wall. As the potential tying run raced home, he threw to his cutoff man, who threw out the runner at home, preserving an Angels victory. It's difficult to decide how to assign value to the three defenders involved in that play, but the conclusion WAR draws is that Trout gets at least some of it. And so, on a scheduled day off, he raised his WAR to a 14.2-WAR pace.

There are home runs, too. There are three-hit games. But this hasn't been a flash-bang season. It's not 73 homers, it's not a Triple Crown, it probably won't even be a Gold Glove. It's marginal gains in every facet of the game. It's a strikeout rate that gets better every year, a walk rate that gets better every year, power that gets better every year, control of the strike zone that gets better every year, even speed and defense that, against the odds, seem to be getting better. It's everything played almost to perfection. Mike Trout is to every other inner-circle baseball superstar what Babe Ruth's 1923 season was to Babe Ruth's discography: the best and somehow also easy to overlook.

WAR is the perfect stat for Ruth's 1923 season. It allows us to understand something we can't so easily imagine, like we can imagine 60 home runs. WAR turns the (relatively) mundane -- scores of walks, an extra play made in the outfield every three weeks, good health, a handful of extra singles and doubles -- into a record. That's what makes WAR perfect for Trout.

But Trout is also perfect for WAR. After all, it can be hard to feel confident about what that 14.1 WAR meant for Ruth: How could that have been better than 60 home runs? We don't have to have any such doubts about Trout. We can see him, we can intuit him, we can break him down every day, and what almost all of us know is he's the greatest player in the world by a mile. The most convincing thing you can say about WAR is Trout leads the league in it every year. How do you design a more perfect stat than that?

All stats through Sunday, unless noted. All WAR figures refer to Baseball-Reference's model.