It’s easy to forget just how crazy football fans thought Mike Leach was before they decided that he was, in fact, a genius. Perhaps the best example of this was his inauspicious debut at the University of Oklahoma.

The year is 1999. Leach has just blown into Norman, along with a new coach named Bob Stoops whose mission is to rescue the Sooners’ declining football program from oblivion. On paper, Leach, the offensive coordinator, is everything you would not want in a football coach, a creature out of the fever dreams of frustrated Oklahoma fans. He has never played college football. He has a law degree from the ultra-effete, Malibu-based Pepperdine University. He surfs. He wears mismatched clothing and speaks in a gnomic, slightly distracted way that might suggest a Chaucer specialist from a small liberal arts college in the upper Midwest. Stoops has hired Leach because Leach and his mentor Hal Mumme have been putting up ungodly sums of points on SEC teams at the lowly University of Kentucky. Under Leach and Mumme, the Wildcats notched wins over Alabama and LSU and wreaked havoc on, among others, the defense of the University of Florida, whose coordinator was Bob Stoops. Stoops has, in effect, hired his nemesis.

Leach has, moreover, publicly promised to throw the ball all the time, which, in the ground-and-pound tradition of Oklahoma football, is something akin to a venial sin. Throwing is for sissies—or worse. Something you do on third down if you absolutely have to. To accomplish his goal, Leach has journeyed to deepest Utah to recruit a sore-armed quarterback with a flawed delivery from a two-year institution called Snow College who transferred from Weber State and plays only half the time at Snow. The quarterback’s name is Josh Heupel. Leach likes his timing and his ability to read defenses. Oklahoma fans think Leach is certifiable. Something close to a revolt follows. “There was a time,” Leach would say later, “when the two most wanted people in the state were me and Josh Heupel.” Stoops stands by his man.

Leach soon proves him right. In the spring intrasquad game, Leach’s offense puts up seven hundred yards on the Oklahoma defense and its flabbergasted coach, Brent Venables. Under Leach, the offense doubles its scoring and goes from 101st in the nation to 11th and from last to first in the Big 12. Leach is immediately rewarded with the head coaching job at Texas Tech. The following year, Oklahoma, running the “Air Raid” offense developed by Leach and Mumme, wins the national championship. Heupel is a finalist for the Heisman.

In the spring of 2009, Texas Monthly dispatched me to the sun-scorched scrublands of Lubbock to write a cover story about Mike Leach. By then Leach had coached the Red Raiders for nine seasons. He had put up a record of 76–39 using players that few or no other elite college programs wanted. For five of those years, Texas Tech had led the nation in offense. In eight of the nine years, his quarterbacks had led the nation in passing. In 2008 he had electrified the football world with his team’s dramatic run at the national championship. In one stretch of the season, the Red Raiders had put up 158 points against the nineteenth-, first-, and eighth-ranked teams in the country, including a spectacular, last-second victory over number one Texas. Though Leach had ultimately fallen short of the title, for a breathless month or so, the nation’s eyes had been fixed on Lubbock and the Red Raiders’ remarkable coach.

So, I went to Lubbock to try to understand this wildly unconventional man.

I had covered enough sports by then to know that coaches and athletic directors were paranoically private, preferring to work in closed sessions in hermetically sealed rooms that were off-limits to most outsiders, especially nosy journalists. In Lubbock, I found an almost shocking transparency. Leach’s entire program, like Leach himself, was wide open. I was invited to attend any coaches’ meeting I wanted. I could talk to any coaches, players, trainers, one-on-one, go anywhere I wanted to go, unsupervised, and speak with Leach himself for as long as I needed. Nothing was hidden. He was charming, funny, engaging, and interested in what I had to say. Sometimes I felt as though I were being interviewed. It was almost impossible to keep him on topic. Everyone I spoke with seemed to like him. His eccentricities—which included long and virtually impossible-to-follow pep talks about pirates and Apaches and surfing and the swinging of swords, both real and metaphorical, as well as a passionate interest in Daniel Boone, the tango, chimpanzees, Napoleon Bonaparte, and Winston Churchill—were viewed with a sort of affectionate amusement.

Curiously, the coach with such a wide range of whimsical interests also had a decidedly tough, old-school side that most journalists missed. When he became famous, he was adopted as something of an anti–Bear Bryant—cute, lovable, and an endless source of oddball quotes. But he could be hard-nosed and uncompromising, and very hard on players when he felt they weren’t giving full effort. The sandpit, where he made injured players do things like drag truck tires hither and yon, along with other forms of hard labor, was a good example of this. If you were hurt, he didn’t let you off; he just found something unpleasant and difficult for you to do. (If the player had an injured arm, he would get leg exercises, et cetera.) This ultrapunitive side of him spilled into the public in December 2009, when Texas Tech fired Leach for what they saw as his mistreatment of a player and then his refusal to admit he was wrong. He had put a player with a doctor-diagnosed concussion in a darkened shed, as though to punish him. The public fight over this, pitting Leach against the Texas Tech administration and famous former football player and commentator Craig James, whose son Leach had put in the cooler, dominated sports headlines for months. Neither side ever admitted fault.

One of the reasons Leach was so unguarded about his coaches’ meetings was that, unlike most coaches, who brandished New York phone directory–size playbooks, Leach had no playbook at all. He often ran only five plays. As one of his former players, Graham Harrell, later told me, Leach would have been happy running only one play. Harrell was only partly joking. When Leach beat number one Texas in the single greatest game in Tech history, he ran that single play—Four Verticals—on four of the last six downs of the game, including the game-winner to receiver Michael Crabtree with one second on the clock.

That radical simplicity has everything to do with Mike Leach’s football legacy. He and Hal Mumme, both together and apart, had an enormous and lasting impact on American football, turning a game that was mostly about running into a game that was mostly about passing. It is hard to get through the broadcast of a college or NFL football game these days without hearing the words “Air Raid” at least once.

Beginning at Copperas Cove High School, in Texas, in the late eighties, Mumme proposed to do something that was almost unheard of in American football at the time: make a full commitment to the forward pass. That meant fifty passes per game, and eventually as many as ninety passes per game. It meant throwing on first down and second down and fourth down. It meant throwing the ball 70 percent of the time—or more. It meant violating that time-tested rule of football that held that the run sets up the pass. Though his system included elements gleaned from LaVell Edwards’s offenses at Brigham Young, Bill Walsh’s West Coast offense, and the Houston-based Run and Shoot, Mumme’s offense—named Air Raid by Leach, who helped tweak it—was his own hybrid, and it outlasted all the others.

In 1989 Mumme was hired by Iowa Wesleyan, a tiny Midwestern college that had gone 0–10 the year before and was one of the worst programs in the country. He received exactly one application for assistant coach. That came from someone named Mike Leach, who at the time was coaching at College of the Desert, near Palm Springs, California, for less than $12,000 a year and planned to coach in Finland that summer, where players smoked cigarettes on the bench. Mumme hired him. It was a match made in football heaven, the utterly implausible pairing of two authentic football geniuses in an obscure town in southeastern Iowa. With Mumme as sorcerer and Leach as sorcerer’s apprentice, they tore up the small-college Midwest and even beat Division II schools ten times their size. From there they went to Division II powerhouse Valdosta State, in Georgia, and then to Kentucky, passing like no one else in the country, setting records, and accumulating mind-boggling yardage through the air.

Just how they did that remains a mystery to most people. In 2017 I published a book about the Mumme-Leach offense, titled The Perfect Pass: American Genius and the Reinvention of Football, whose purpose was to answer that question. Broadly speaking, the answer was that the Air Raid of Mumme and Leach’s design—by the time they were at Kentucky, they were in a full partnership—produced a system in which their teams were playing a different game of football, by entirely different rules, than their opponents.

If that sounds strange, listen: the first and most obvious difference was that the Air Raid was disarmingly simple. With no playbook and only a handful of plays, Leach’s team was able to practice each one many times; the opponents, with many plays, had only a few reps for each. The Air Raid, as measured by the number of plays and formations, was simpler by far than anything else that was being done and easy for players to understand. Meanwhile, the opposing defense would see a whirring, multidimensional machine that looked so intricate and complex that, even though defensive coaches watched it over and over again on film, they still couldn’t stop it.

But simplicity against complexity was just the beginning of this Mumme-Leach experiment in relative advantages. Their teams played blindingly fast, running at high speed with no huddles for entire games, thus routinely executing as many as 50 percent more plays in a single game than their rivals. No one else did this. The Air Raid squad played a game that featured as many as 90 plays on offense; their rivals usually averaged around 65.

While opposing teams relied on schemes that made the field small, circumscribed by their traditional ideas of run-it-up-the-middle offense, Air Raid teams operated on a vastly larger pitch, stretched both vertically and horizontally by the passing game. One way the Air Raid did this was by putting enormous spaces between their offensive linemen—as much as six feet—more than anyone had ever done before. This sounds crazy: in fact, it was hugely effective, pushing edge rushers far away from the quarterback and opening wide passing lanes. Even the line of scrimmage was different for both teams. Leach and Mumme were messing with space as well as time.

Their teams played with entirely different assumptions about one of the game’s fundamental rules: the number of downs a team gets to make a first down. Because Air Raid teams disdained punting and even kicking field goals, they got four chances to advance ten yards, while standard in most of American football was three and out if a team failed to make a first down. At Texas Tech, Leach became famous for going for it on fourth and six from his own thirty-yard line. (In the stands once in Lubbock, I saw many Tech fans cover their eyes when this happened.) This challenged yet another fundamental assumption: in a four-down set with no punt, the opponent’s third down became the Air Raid’s second down, leaving defensive coordinators who ran their standard third-down packages wrong-footed against Leach’s teams—and ill-prepared to stop them.

Even the goals of the game were called into question. While the other team was convinced that the main objective of football, other than winning, was to dominate time of possession, Leach and Mumme played as though that statistic were irrelevant. They didn’t care about time of possession, only about scoring. Grinding it out, in their view, was a tactic that belonged in the nineteenth century.

Their practices were radically different, too. They were short, with only light hitting. There was no stretching at all. These were heresies. It was all geared toward forcing opponents to play on their terms, in their alternate universe, where they had all the advantages.

Though Mumme and Leach ran their offense successfully for a decade, the big shift in American football toward the Air Raid style of offense didn’t start until 1997, when, at the University of Kentucky, the Wildcats began to put up huge passing numbers against the SEC’s lockdown defenses. Almost no one believed this to be possible. The Air Raid came into brilliant focus on October 4, 1997, when Kentucky took on rival Alabama, a team it had not beaten in 75 years, and won 40–34. The following year, a large part of the American football world showed up at Kentucky’s football camps to try to figure out how they had done it.

In the years to come, while Leach coached at Texas Tech, Washington State, and Mississippi State and Mumme pursued his own, separate career, Leach held to a remarkably pure form of the offense that he and Mumme had developed decades earlier. He had great success. At Washington State, he was twice voted the Pac-12 Coach of the Year and once the AFCA Coach of the Year. Washington State led the nation in passing offense in four of his last six years there, and in that time it never finished lower than third. This year, with Mississippi State, he was starting to make inroads in the daunting SEC.

Meanwhile, his coaching tree has spread and branched. His disciples include Lincoln Riley (USC), Kliff Kingsbury (Arizona Cardinals), Dana Holgorsen (University of Houston), Sonny Dykes (TCU), Josh Heupel (University of Tennessee), Neal Brown (West Virginia), Sonny Cumbie (Louisiana Tech), Dave Aranda (Baylor), and many more. Since that pivotal Alabama game in 1997, the Air Raid has gained rapidly in popularity and visibility. Its influence is now unmistakable at all levels of football. When Tom Brady throws touchdowns using Air Raid plays like mesh and Y-cross, or when top college offenses play entire games at two-minute drill speed and throw for more than 400 yards, these are Air Raid legacies. When Washington State quarterback Connor Halliday throws for a mind-numbing 734 yards against the University of California, that is the Air Raid in action.

When I interviewed Leach in Lubbock in 2009, I asked him where his offense had come from, and he answered by telling me about the miraculous, world-beating football team at Iowa Wesleyan and its genius coach, Hal Mumme. He then told me about cross-country trips he and Mumme would take in Mumme’s old car, looking for coaches who would help them learn how to improve their passing offense. Now that he’s gone, I will always see him that way, out on the great frozen Midwestern plains, with his buddy and mentor, looking for the secret of the forward pass.