'Lethal Allies - British Collusion in Ireland' looks at 120 murders carried out in Mid Ulster and the border region between 1972 and 1976 and evidence of co-operation between police, army and loyalists.
The book draws investigation reports compiled by Historical Enquiries Team as well as 15 years of research by the Pat Finucane Centre.
It describes how loyalist paramilitaries killed people on both sides of the border, and that "beyond a doubt" a significant number of members were also serving in the RUC and UDR.
All but one of those who were killed were found to be innocent and "upwardly mobile" Catholics with no links to paramilitaries, and at least six victims were linked to the SDLP.
One of the cases examined was that of the UVF bombing of the Step Inn in Keady in August 1976, which claimed the lives of two Catholics, Elizabeth McDonald and Gerard McGleenan.
Speaking for the first time in the 37 years since the incident, bar owner Malachy McDonald, who lost his wife Elizabeth in the blast, said he simply wanted to see the truth come out.
I can't forgive anybody - the person that they murdered is the only person (to do that) and she's dead.
"Whenever I got into the back, I found Betty lying there on the steps at the back of the bar, with her blue eyes protruding wide open and her mouth wide open," Mr McDonald recalled.
"Whenever I turned around, Laurence (their four-year-old son) was beside his mammy."
The book found that RUC Special Branch were aware of a planned car bomb attack 10 days before the incident and that the Army had been called in to monitor a house in Glenanne, where they believed the device was being stored.
The property belonged to a part-time police officer.
Military surveillance was lifted and the 'Glenanne gang' merely changed their target to the bar in the Co Armagh village. After the bombing, the RUC did not make any arrests.
A previously unpublished HET report said: "There was no reasoning or rationale anywhere in the papers examined for leaving the bomb unrecovered.
"It may have been a speculative decision, hoping for more exact intelligence, it may have been about protecting the identity of informants; if so it was a huge gamble which went catastrophically wrong."
Speaking about her book, author Anne Cadwallader said: "For 30 years as a journalist in Northern Ireland, I'd often heard collusion being used again and again - it became a degrading and debased word as it was used so often with no proof.
"This book has the proof."
The truth really matters to this society - we can't build a shared future on a past that we're divided about.
Anne Cadwallader, author of Lethal Allies
Ms Cadwallader added: "This book has the proof because the Historical Enquiries Team has lifted the carpet, and we can all see for the first time what has been swept underneath. How much more is there under that carpet?"
"If we can move forward together, having learnt the real truth of what happened here during the conflict there is hope for this place."
The Pat Finucane Centre, which produced the book, said: "Lethal Allies concludes it can be demonstrated, beyond a reasonable doubt, that there was systemic collusion in these cases and that such denials of human rights never contribute towards peace but merely serve to fuel conflict."
A statement added that the collusion "fuelled the conflict as Catholic confidence in the RUC and UDR collapsed leading to public support, or tacit toleration, of violent republicanism".
As a result of the HET investigations, over 20 families have now taken formal complaints to the Police Ombudsman.