What happened in the small Northland town in the early hours of August 4, 1979, was a pivotal point in gang history. It was the first time gangs had attacked the police and the public. It led to sweeping anti-gang legislation. It features large in Gilbert's Patched.
The "Moerewa riot", as it has always been known, was a shocking eruption of violence between Auckland-based Stormtroopers and local Black Power members, the savagery then directed at the thin blue line trying to break them up.
Several people were injured - among them a policeman beaten and kicked nearly to death, another bashed and almost forced into a police paddy wagon the rioters had set on fire while others suffered burns, smashed teeth and broken bones.
Firemen bolstered that thin blue line even as Molotov cocktails were thrown at them, and their fire engine smashed up.
The rioters were armed with chains, iron bars, bottles and clubs; the police had at least one gun, and long wooden batons so useless New Zealand Police immediately kitted out the whole force with a shorter, flick model. Police were also later issued with riot gear that included helmets and body shields.
That night, in the hotel car park-cum-battlefield, shotgun blasts ripped through the sound of glass smashing, fighting and a blazing vehicle.
As things began to quieten, lying among the injured was a gang member shot in the legs with a police pistol.
Twenty five Stormtroopers and Black Power members were convicted on charges including causing grievous bodily harm and criminal damage.
Initially that night, there were only eight police officers. By the time reinforcements arrived, the Moerewa riot was all over bar the shouting.
THE SHOUTING would thunder through the community (for another generation at least), the media and the halls of the lawmakers, resulting in increased police powers against gangs.
Moerewa had essentially been a turf war, a cause as old as the patched gang culture in New Zealand, Dr Jarrod Gilbert said.
That culture had its genesis in the 1950s but the '70s and '80s were the setting for "massive gang violence and crime". Some gangs identified themselves as Maori (a lost generation who had rejected their own as well as mainstream society ), bikers, urban and other ethnicities.
Different types of gangs have emerged more recently, such as LA-style youth and Asian gangs, but the 1960s, and still today, there were four main gangs - Black Power, Mongrel Mob, Head Hunters and Stormtroopers. Biker gangs, almost moribund a decade ago, are on the rise again but unlikely to gain a huge standing, Gilbert says.
All gangs represent a community of their own, organised and with strict codes, hierarchies and roles. Their targets and enemies have always been each other, sometimes in retribution their own, seldom the general public, Gilbert says.
"Gang violence and gang crime exists almost exclusively in the underground. The general public have a largely unwarranted fear of gang members."
They remain attractive to young, rebellious people seeking some kind of status or belonging that they can't achieve by conventional means, he said.
"Gangs will always endure but there is a tremendous amount of myth that surrounds gangs. They
are analogous to sharks. Most people are scared as hell of them but very few will ever actually be harmed by them. Nevertheless, as we all know, they have perpetuated some horrifying crimes in this country," Gilbert said.
"Gangs are a major focus for police, but I argue that the police paint an extremely distorted view of the gangs. This is an extremely controversial finding, but the book allows me the room to take people through all of the evidence."
Against the backdrop of '70s political unrest and a growing consciousness of Maori grievance, "there was a genuine concern the gangs could become politicised," Gilbert said.
But they haven't, beyond the inherent politics of poverty in which gangs manifest. For 10 years Gilbert was allowed inside the fortress where most people cannot go, from where the gangs' own stories emanate.
Gangs never talk to the media, their public perception is often stated through the police or courts, and while legislation has been shaped because of them, there has been little academic rigour or analyses to back it up. It was the latter fact that spurred Gilbert's "non-threatening, non-judgmental" research.
He cuts it down to: "They exist, I study them."
Yesterday's gang members are now men in their 60s and 50s, they are grandfathers; they no longer have the furious energy of youth.
But their gang culture lives on and, as traditions and communities, is evolving. Among positive changes is how whanau and family are respected, and women are viewed, Gilbert says - "The plight of women in the early history of gangs was diabolical."
Today, gangs are a permanent presence and deeply embedded in society.
"If you've got certain social conditions - poverty and dysfunction and a disconnect (with roots) - you will have gangs. They will be there at the sharp end of hardship.
"If we are happy to accept those social and economic conditions, then we must be prepared to accept gangs."