After a 2006 game between the Minnesota Twins and the Boston Red Sox, a clandestine meeting took place in the rear laundry room of Minnesota’s Metrodome between the managers of both teams and Twins center fielder Torii Hunter.

In a gesture that would have made Don Corleone proud, Twins manager Ron Gardenhire brought his player to inform Red Sox skipper Terry Francona that a transgression Hunter had committed during their just-concluded game was done out of “inattention, not disrespect.” Francona appreciated the gesture, and a crisis was averted.

And what was this dire criminal offense that led Gardenhire, driven by a mix of protocol and fear of igniting a war, to prod his player toward the baseball equivalent of kissing the opposing Capo’s ring?

He swung at a 3-0 pitch with an 8-1 lead.

Unbeknownst to most outsiders, all aspects of baseball — from hitting, pitching, and baserunning to dealing with management and the media — are governed by the Code, a complex series of unwritten rules that have evolved since baseball’s earliest days.

This Code, which the authors describe as “less strategic than moral,” includes behavioral rules for common baseball situations; the punishment for flouting those rules; and the “omerta” that ballplayers must never, ever, discuss the rules of the Code outside the clubhouse.

The “cessation of aggressive tactics during a blowout” are a major part of the Code.

In 1996, when then-Dodger rookie Roger Cedeno stole second base with the first baseman playing deep and his team ahead 11-2, he was verbally abused by Giant players. But it was one of his own teammates who then approached the Giants bench to alert them that Cedeno had run “without a shred of institutional authority,” and that “justice” would be meted out internally. (While it’s not reported what form that justice took, Cedeno was later seen crying in the clubhouse.)

The Code also punishes certain players for infractions that would be fine for others. When the Cubs’ Bill Buckner slid hard against Pirate second baseman Phil Garner, it caught Garner off guard because Buckner normally slid short. This made it a Code infraction, and the next time Buckner ran for second Garner fired the throw toward his head. Buckner raised his hand in defense, and the ball broke his finger.

As veteran sportswriters Turbow and Duca lay out in this remarkably well-researched book, filled with intricate details of plays from the past 100 years, the Code has affected careers, long-boiling team rivalries, World Series victories, and the game’s most hallowed feats in surprising ways.

In the 1980 World Series, the Royals, down 0-2, took game three and were leading game four when Willie Mays Aikens committed the cardinal sin of lingering in the batter’s box a few seconds too long to savor a home run.

When the next batter, Hal McRae, pumped his fist after a double — another tremendous violation for the way it shows up the other team — the gauntlet was thrown. Enraged Phillies pitcher Dickie Noles retaliated against the Royals best hitter, George Brett, slamming him to the ground with a fastball aimed right at his head. That pitch, and the ensuing screaming match, sapped the Royals’ momentum, and helped propel the Phillies toward a series win.

As much as the Code abhors showboating, it reveres history, to the extent that teams will extend courtesy to record seekers even at their own expense.

The week before Yankee great Mickey Mantle retired, he had 534 lifetime home runs, tying him with Jimmie Foxx on the all-time list. Before a game with Detroit, Tigers pitcher Denny McLain told his catcher to let Mantle hit one out, and the catcher shared the good news with Mantle at the plate. The slugger pointed to where he wanted the pitch, and thats where McLain threw it, gifting Mantle with No. 535.

And Roger Maris’ history-making season in 1961 was achieved with the help of another Code quirk — its tolerance of stealing pitchers signs, which is just a normal part of the game according to the Code. When Maris stepped to the plate to take a swing at a record-breaking 61 home runs, a whistle from the third base coach let him know that a fastball was on the way.

Cleveland Hall of Famer Bob Feller brought a military-grade gun sight back from World War II. After an August slump, the team used it to set up a spy station in their scoreboard that led them to a 19-5 resurgence, and the 1948 World Series championship.

Teams have used fake TV cameras in the outfield, flashing lights in their scoreboards, and even buzzers wired from the bullpen to the clubhouse, as Bobby Thomson’s ’51 New York Giants did in going 20-5 en route to his infamous “Shot Heard ‘Round the World” playoff homer.

But the one method of sign stealing that is unacceptable is for a batter to peak at the catcher while he gives the signs. When Royals outfielder Al Cowens was caught doing just that in 1979, the Texas battery responded with a fake outside pitch call that actually came up and in, breaking Cowens’ jaw.

The most important aspect of the Code is its penchant for loyalty. If a fight breaks out, every player must find themselves on the field in their team’s defense, a rule so important that Yankee Luis Tiant once bounded out of the shower during a brawl wearing nothing but a towel.

But while the Code is rigidly adhered to, it does have some maverick opponents who feel that following its rules means that you’re not playing to win.

Base-stealing champ Lou Brock made it clear throughout his career that he would steal bases no matter how big his team’s lead was. As Brock’s Hall of Fame teammate and admirer Bob Gibson tells it, “He’d say, ‘F – – – you. I’m gonna do it.’ His attitude was to beat the other team as badly as possibly, and that was my kind of baseball.”

BAT MANNERS:

* Yankee great Lou Gehrig played for 2,130 consecutive games, a record that stood for 56 years. But he was helped along the way when Yankee general manager Ed Barrow called a rainout on a day when there was no rain because Gehrig was home, bedridden with the flu.

* The Code rule declaring that every ballplayer MUST join their teammates on the field if a brawl broke out has led to some ridiculous sights. Relievers from opposite teams would run out from the bullpen — chatting friendly right next to each other — then hit the field and start battling. And during a brawl with the Milwaukee Brewers, Yankee pitcher Luis Tiant joined his teammates straight from the shower with nothing but a towel around his waist and a cigar in his teeth.

* Thanks to the Code, there may have been no one who contributed more to Yankee greatness than pitcher Bob Turley, who figured out what opposing pitchers were going to throw just by watching them, and alerted Yankee batters with a whistle when a pitch was different than the last. One indirect recipient of his talent was Roger Maris, whose record-breaking 61st homer of 1961 came on a fastball he knew was coming, right after third base coach Frank Crosetti — who learned everything he knew on the subject from Turley — put his lips together and blew.

* In 1993, 46-year-old Texas Rangers pitcher Nolan Ryan humiliated the half-his-age Robin Ventura of the White Sox with a pounding to the skull so one-sided it recalled the Bill Murray/Gilda Radner noogie sketch from “Saturday Night Live.” The fight was the result of a three-year feud between Ryan and the White Sox over the elder superstar’s aggressive adherence to the Code’s retaliatory measures — mainly, his frequent beanballs.

* Cardinal great Bob Gibson believed that the Code entitled him to knock down any batter who bested him with a grand slam. So when the Chicago Cubs Pete LaCock did just that, Gibson felt he owed him one — unfortunately, the homer came during Gibson’s final game. Gibson finally took his revenge 15 years later, plugging LaCock in the back during an Old Timers Game.

* When the Yankees took on the Angels in 1987, the announcers discussed how Angels pitcher Don Sutton was scuffing the ball. Yankee owner George Steinbrenner, hearing this on TV, called Yankee manager Lou Piniella in a rage, demanding that the umpires inspect Sutton’s glove. Piniella had to explain to the Boss, “The guy who taught Don everything he knows about cheating is pitching for us tonight. Want me to get Tommy John thrown out too?”

The Baseball Codes

Beanballs, Sign Stealing, and Bench-Clearing Brawls: The Unwritten Rules of America’s Pastime by Jason Turbow with Michael Duca

Pantheon Books