The end of Liverpool’s Jürgen Klopp era was just three months ago, but already the first insider account of those remarkable nine years has been written – and it is one of the great football books of its time, not just for what it says about Liverpool but also the game now.

Its author Ian Graham predated Klopp at Liverpool by four years and is the architect of the data analysis model that was a key part in assembling the great Klopp side. Roberto Firmino, Sadio Mané, Mohamed Salah, Andy Robertson, Alisson Becker and Virgil van Dijk were all among those subjected, pre-acquisition, to the model created by Graham’s research department. Graham has a physics PhD from Cambridge and four years seconded to Tottenham Hotspur – neither of which represented a guarantee of success at Anfield. Nevertheless, the results were astonishing.

Before and during the Klopp era, an intriguing cast of characters converged to build a team that would win the 2019 Champions League and then the club’s first league title in 30 years. Key among them was Michael Edwards, now back at the club, but earlier a disputatious Spurs video analyst who later rose to power at Liverpool and appointed Graham.

“It’s all b------, isn’t it?” Edwards said years earlier, Graham writes, when he first asked the latter to explain his model while at Spurs. In spite of that robust opening exchange, Edwards champions Graham’s work. Over the years that follow, the pair combine Graham’s model, as well as Edwards’ video analysis, with conventional scouting, salary data and hard-headed negotiating to sign players who markedly outperform the squads of wealthier rivals.

The book’s bold title is How to Win the Premier League. Ambitious by any measure but in this case, entirely justified. It has everything. The feisty internal politics of an ambitious Premier League club. The external pressure of a restless fanbase and a sceptical media. The distant hand of a super-rich ownership group.

Also: a lot of dense statistical concepts.

Exploiting wattage of Klopp’s personality

There is an insider’s take on Klopp himself. He is collaborative, at times, and demanding. Highly competitive, opinionated when it comes to players and also a great salesman. It is the wattage of his personality that means the players who make it to the top of the lists compiled by Edwards and Graham joined Liverpool instead of rivals.

“It doesn’t happen this way without Jürgen,” says Graham, when we meet for lunch ahead of the book’s serialisation. “Some of the main things he brought were clarity of thinking with tactics. He was absolutely clear what was needed and with a different manager you might not get that. The fact that players want to play that kind of football and play for Jürgen. Do we sign Van Dijk if it is a different manager?” He pauses. “You would have to ask Van Dijk.”

Yet, even so, over three hours of conversation, there is the nagging question: why did they eventually all leave? First Edwards, then Graham in 2022 and others too. By the time Klopp himself announced his impending departure in January many of that core staff had been hollowed out. The famous Liverpool scouts Barry Hunter and Dave Fallows remained, but even Edwards’s deputy, and erstwhile successor, Julian Ward lasted just six more months. Then another twist: once Klopp announced he was leaving, Edwards and Ward returned to senior roles.

“In the book I talk about the arguments,” Graham says. “Even when we were aligned, alignment is not the same as group-think or harmony. It’s healthy but it’s hard. And it is hard to go into the 10th transfer window knowing you are going to have massive arguments because everyone wants to make the right decisions. The right thing to argue about. But it has a lifespan.

‘The Beatles were only together for 10 years’

“Michael reached the end of the road because he was closer to the coalface than I was. He was the one having to have the arguments, not just with Jürgen, but with owners, agents, players. I cannot speak for Michael but from the outside … even though my job is less stressful day to day, it has a lifespan. The Beatles were only together for 10 years. They had loads of arguments but they created some good music. You’d have to ask the Beatles, but those arguments probably made the music better.

“The idea we couldn’t stand Jürgen anymore and therefore left – it’s a caricature. Jürgen’s success obviously brings acclaim but the structure was always in place, just as it was with Brendan [Rodgers, his predecessor]. And everyone has problems with that structure if things aren’t going their way. I had problems with that structure when I thought players should be signed [and] Michael or Jürgen vetoed for whatever reason. Those tensions existed, absolutely. They weren’t really the direct reason for me leaving.”

Edwards is now back at the heart of it, the chief executive for football for Liverpool’s owners Fenway Sports Group. It was Edwards who appointed his former Portsmouth colleague Richard Hughes as the new sporting director and from there came Klopp’s successor, Arne Slot. Edwards had played a part in Graham launching his sports data consultancy, Ludonautics. That is Graham’s day job now, while Edwards’s return to FSG means he has cut all ties with the company.

Benteke deal encapsulates gripping power-struggle

Graham, 46, grew up in South Wales, in a village near the Brecon Beacons, and taught himself football and computers through a heady mix of Subbuteo, football yearbooks, and the Amstrad his mother brought home from work. An academic high achiever who was an undergraduate at Cardiff University, he has become a leading figure in football data analytics.

He is also an accomplished writer. How to... is very funny at times, especially on the subject of Graham’s struggles with Rodgers, the Liverpool manager who fought Edwards and Graham’s new approach all the way to his 2015 sacking. The story of the club’s ill-fated acquisition of Christian Benteke details a gripping power-struggle destined to end in tears. Rodgers’s obsession with signing the Belgian, Graham notes, “made Captain Ahab’s fascination with Moby Dick look like a passing fancy”.

As he and Edwards become ever more desperate to dissuade Rodgers from pushing the Benteke deal with FSG, Graham considers quoting Oliver Cromwell’s speech to the Scottish church, to the then Liverpool manager. “I beseech you, in the bowels of Christ, think it possible that you may be mistaken”.

That quotation gives its name to statistics’ Cromwell’s law. Neither statistics, nor data, nor scouting ever looked right on Benteke. Eventually Rodgers insists on the player, who goes on to perform exactly as predicted. What will Rodgers make of the book? “I don’t care,” Graham says. “With the benefit of hindsight, you think: ‘What was Brendan thinking?’ But at the time, data analysis was untried [in football]. Director of football [concept] had been seen to have failed. Brendan was younger than I am today, manager of Liverpool after being manager of Swansea City.

“He was seen as a modern manager and he portrayed himself as a modern manager. He was not a modern manager. He made it clear he would not run the club that way [with collaboration on recruitment] and all the problems came from that. My interpretation is that it stemmed from insecurity. The only way he would feel secure in the job is if he was in control. He never made progress with it. After the 2013-14 season and [signing Daniel] Sturridge and [Philippe] Coutinho we had made the first step. There was never any progression. To the final day [it was]: ‘Things have to be my way and it has to be my choice of player coming to the club.’”

As Graham is at pains to point out, his analysis model, which grows in sophistication over the years, does not have all the answers. But it does offer a way of trying to make rational decisions in an industry where billions are spent on transfers. Indeed, his analysis concludes that only 50 per cent of transfers can be considered a success. He is honest about the failures: Lazar Markovic, Iago Aspas, Luis Alberto and his own Ahabian obsession, Naby Keïta, who never quite hit the heights.

Klopp, the book records, first wanted Mario Götze over Mané and initially preferred Julian Brandt to Salah, although when I point that out, Graham is defensive of Klopp. “You are falling foul of hindsight,” he says. “When we were having those discussions, you cannot take anything from their future careers into account.” Both the German players, says Graham, were on the list and worthy of consideration. The difference was that, unlike Rodgers, Klopp was ready to be persuaded.

‘Better to be a serious nerd than a frivolous nerd’

Graham is different to the characters one usually encounters in football. He is not interested in burnishing reputations or anything else that gets in the way of identifying any error that, once eliminated, will improve his model. It would be fair to say he is no more likely to turn up for an interview in a pair of Balenciagas than he is to ignore standard deviation. Although he has certainly not forgotten any of the vitriol directed at him or Edwards over the years by football people or journalists.

Much of it is quoted in the book and I read one back to Graham in which he is described as, among other unflattering epithets, “a serious nerd”.

“Better to be described as a serious nerd than a frivolous nerd,” he says. “If you sign up to work for Liverpool you sign up to this nonsense. You shouldn’t have to but that is the way it is.” He points out that when The New York Times interviewed him before the 2019 Champions League final, the journalist asked Graham for a list of detractors and on-the-record sceptics about data analysis. The journalist then contacted all of them for the opposite side of the argument. None were, by then, prepared to do so.

“I tried to be truthful with all the things we did wrong as well as the things we did well,” he says. “And I was trying to say … those reports I quoted were what the outside world thought of us in 2015.” Later we return to the subject when I ask Graham if the book is an attempt to reclaim data analysis from those who seek to portray its architects as outsiders, intent on stripping away the mystique of the game.

“I wanted to be honest about what role data analysis played,” he says. “There is this caricature that is too positive, of geniuses. That this mysterious stuff they do is such an edge. We are not geniuses. It’s not mysterious. It brings an edge but only when it is implemented properly. The stuff we do doesn’t make any difference if you don’t have someone like Michael making the decisions. If you don’t have Jürgen who can attract players and has a good tactical plan.”

His partnership with Edwards is critical. The latter was a former academy player with an IT degree and an early career with ProZone, the first big football data company. Edwards could inhabit the conventional football world – of players, managers and agents – while understanding enough about the sophistication of Graham’s work to help him improve his model.

Graham is a football fan like the rest of us – and grew up absorbed by it. A career in data analysis has not changed that. Rather it has, he says, deepened his appreciation of the game’s beguiling complexities. He points out that one does not have to understand the mathematics behind JS Bach’s Well-Tempered scale to appreciate Bach, although doing so can add a new dimension. Needless to say, Graham does understand the mathematics behind the Well-Tempered scale.

He is blunt about how the same advantage has been wasted at other clubs in the past. Strong data analysis departments at Arsenal and Barcelona were largely ignored for years. How to... makes clear that no one at Liverpool can understand what on earth is going on at Manchester United. “Nearly everyone,” Graham notes, can improve performance via expenditure “with the notable exception of the Glazer family”.

In the end, the results were plain to see. During the 2017 summer that Liverpool signed Salah for £37 million, Graham points out that Chelsea spent £58 million on Alvaro Morata, Arsenal signed Alexandre Lacazette for £46.5 million and Romelu Lukaku joined United for around £90 million.

Year after year, Liverpool outperformed their budget. Edwards’s great challenge is to do it again, without Klopp. The Beatles have partly reformed, although the line-up is missing one of either Lennon or McCartney, depending on how you look at it. As for Graham, also gone, who might he have been in the original ensemble? The shrewd observer may say George Martin.

‘How To Win The Premier League’, by Ian Graham, is published by Century, Penguin Random House. £22, available now