Pakistan and India have fought four bloody wars since their creation in 1947, and continue to engage in daily clashes in the divided Himalayan region of Kashmir.
So for the former intelligence chiefs of the two nuclear-armed foes to co-author a book that sheds light on their efforts to outmaneuver each other would appear almost unthinkable.
Yet that is exactly what retired General Asad Durrani, head of Pakistan's Inter-Services Intelligence (ISI) between 1990 and 1992, and his counterpart A.S. Dulat, who led India's Research and Analysis Wing (RAW) from 1999 to 2000, did.
Their book, Spy Chronicles: RAW, ISI, And The Illusion of Peace, is based on secret discussions held between the two former spy chiefs in hotels across Asia. Indian journalist Aditya Sinha organized and oversaw the effort, and put the results to paper.
In an exclusive interview with RFE/RL's Radio Mashaal, Dulat says "these are the perceptions of two people from opposite sides. Every word is as true as we know it to be."
The unprecedented book makes head-turning revelations about the conflict in Kashmir, Pakistan's covert role in the war in Afghanistan, and the U.S. raid that killed Al-Qaeda leader Osama bin Laden in Pakistan.
In India, the book has received a mostly positive reception, and Dulat has given televised interviews. But in Pakistan, Durrani's claims -- often in conflict with the official line -- have been widely criticized. He has been summoned by the military to explain himself. He has also been forbidden from leaving the country.
Below are the book's most eyebrow-raising revelations:
Pakistan's Complicity In Bin Laden Raid
In 2011, a team of American Navy SEALs flew into Pakistani territory from Afghanistan and killed bin Laden inside the secret compound in the northern Pakistani city of Abbottabad where he had hid for nearly a decade. Pakistan insisted it only knew of the U.S. operation after the team that carried out the raid had left the country.
"At some stage the ISI probably learnt about it [the compound] and he was handed over to the U.S. according to a mutually agreed process," Durrani suggested in the book, a scenario that would contradict Islamabad's official line.
"Perhaps we are the ones who told the Americans…we are going to feign ignorance," added Durrani, going on to speculate why the government denied prior knowledge of the raid. "If we denied any role, it may have been to avoid political fallout. Cooperating with the U.S. to eliminate a person regarded by many in Pakistan as a 'hero' could have embarrassed the government."
"For Pakistan, being blamed for incompetence was more acceptable than complicity," he wrote. "How could it not know [about] the U.S. helicopters ingressing 150 kilometers inside the country?"
Following the raid, Islamabad accused Pakistani doctor Shakil Afridi of running a fake vaccination campaign that he used to collect DNA samples from bin Laden family members to help the CIA track him down. Afridi has not been charged over those allegations.
But Durrani wrote that Afridi was not the only person to have discovered bin Laden's whereabouts.
"I have no doubt that a retired Pakistani officer who was in intelligence walked in and told the Americans," wrote Durrani, suggesting that the officer received part, if not all, of the United States' $25 million reward for information leading to bin Laden's capture or death.
Dulat wrote in the book that India's assessment "is the same. That he [bin Laden] was handed over by Pakistan."
In an interview with RFE/RL this month, Dulat expounds on his comments, alleging that "Pakistan was harboring Osama and the Pakistanis knew where he was and I think the Americans somehow got wind of this and they told the Pakistanis that 'look, we know where he is,' and then [said] to 'stay out of it.' Maybe there was a CIA mole in Pakistan, and General Durrani has also hinted at that."
Pakistani Support For Afghan Taliban
Afghanistan, the United States, and India have long accused Pakistan of providing safe havens to the Afghan Taliban on Pakistani territory, and of failing to go after the militants, claims Islamabad has consistently rejected.
Yet in 2016, Sartaj Aziz, a top foreign affairs adviser for Pakistan's government, admitted publicly for the first time that Islamabad has considerable influence over the Taliban because its "leadership is in Pakistan."
In 2015, former military dictator Pervez Musharraf revealed that there were Pakistani-backed militant "proxies" in Afghanistan.
In the book, Durrani added more weight to the widely held belief that Islamabad turns a blind eye to the Afghan Taliban's presence in Pakistan.
"[By] going against them, we would not only turn some more of our own people against us, but also these groups who have never harmed us," he wrote.
Durrani wrote that, after the U.S.-led invasion toppled the Taliban regime in 2001, "Pakistan did try to help with whatever was possible despite the pressure" from the international community to cut ties with the militant group, which Islamabad had recognized and supported during the group's rule from 1996 to 2001. "To lose that capital would be something from which you may not recover," he wrote.
India has been a key ally of the Afghan government and spent billions in infrastructure projects. Pakistan has also accused New Delhi of trying to encircle it by expanding its activities and influence in Kabul.
Speaking to RFE/RL, Dulat says New Delhi understands that "Pakistan has more stakes in Afghanistan" but that "India cannot be wished away from Afghanistan."
Dulat also says New Delhi has "banked too much on the Americans" in Afghanistan and should play a bigger role in the peace process. "I don't know if [India] is talking to the Taliban but I am very clear we should be talking to the Taliban. If we are engaged with the Taliban, very good. If we are not, I think it is high time that we did engage."
Pakistan's Support For Kashmiri Rebels
India and Pakistan have fought two wars over the divided Himalayan region of Kashmir, which both countries claim.
Rebels in the majority-Muslim region have been fighting Indian rule since 1989. India accuses Pakistan of arming and training anti-India rebels. Pakistan denies this, saying it offers only moral and diplomatic support to the militants and to Kashmiris who oppose Indian rule.
Nearly 70,000 people have been killed in the uprising and the ensuing Indian military crackdown.
"When the Kashmir uprising happened we did not know how far it would go," Durrani wrote. "We didn't want it to go out of control, which would lead to a war that neither side wanted…. ISI's leverage on the Kashmir insurgency turned out less than successful."
Durrani also suggested that Pakistan created the All Parties Hurriyat (Freedom) Conference, the main alliance of separatists in Indian-controlled Kashmir, to peddle its agenda in the region.
"Going back to the evolution of the Kashmir uprising of the 1990s, I think the formation of the Hurriyat to provide a political direction to the resistance was a good idea," he wrote. "Giving up handle on the movement -- letting the factions do what they bloody well wanted to -- was not."
Most Kashmiris support the rebel cause while also participating in civilian street protests against Indian control. New Delhi has been accused of ruthlessly cracking down on the demonstrators.
"Sometimes [the situation in Kashmir] gets so bad that there comes a state of hopelessness," Dulat tells RFE/RL. "Engagement is the key to the Kashmir solution. But we have not engaged them sufficiently."
Perhaps Durrani's most eyebrow-raising suggestion for peace is the reunification of the subcontinent into a confederation like the European Union.
Pakistan and India were carved out from British India that was partitioned in 1947, creating a Muslim-majority Pakistan and Hindu-majority India.
"We can consider moving to a confederation, and then to a united India," wrote Durrani, in remarks that have riled hard-line conservatives on each side of the divide.
"Right now it's impossible to create a coalition or a union like the European Union, whose relevance is itself in doubt, but at some stage we can think of a common currency, or laws applicable to when we develop the new South Asian Union: a Confederation of South Asia," he wrote. "Delhi as the capital of a Union. Armed forces integrated. Reduction of forces numbers by ratio."