Khan shunned the media in his later years
During a career spanning nearly 50 years, Ghulam Ishaq Khan was at the centre of some of the most important developments in Pakistan's stormy history.
But the former president, who has died aged 91, kept his version of events to himself and his secrets have now gone to the grave with him.
In 1955, when the entire western wing of the united Pakistan was grouped into a single province, Khan became its irrigation secretary and was involved in negotiations that led to a controversial river water distribution treaty with India.
The treaty still continues to be a source of friction between the Pakistani provinces of Punjab and Sindh.
Over subsequent years, Khan remained the head of the powerful Water and Power Development Authority (Wapda).
He was the federal finance secretary when Bangladesh seceded from Pakistan in 1971, and acted as the government's representative in facilitating the transfer of power from a defeated military regime to the civilian government.
Khan was then made head of the central State Bank of Pakistan by the democratic government that followed, and was elevated to secretary general of defence in 1975, thereby becoming privy to details of Pakistan's nuclear programme.
He retired in the early years of the regime of General Zia ul-Haq regime, but his abilities as a technocrat and his loyalty to the civil-military bureaucratic combine as opposed to political forces made him an invaluable asset for the military regime.
General Zia appointed him his adviser on finance, and later elevated him to federal minister for finance.
In 1985, when partyless elections were held, Khan became the government's candidate for a Senate seat.
Soon afterwards, he was elected as the Senate chairman, a position that made him the constitutional successor to the presidential office if the incumbent died or became incapacitated.
When General Zia did die, in a plane crash in 1988, Khan assumed charge as the acting president, thereby ensuring a smooth transition from military to civilian rule.
But he helped the military manipulate the political atmosphere, and presided over the country at a time when the ISI intelligence agency created the Islami Jamhuri Ittehad (IJI) alliance to counter the populist Pakistan People's Party (PPP).
In 1990, Khan's name was mentioned in connection with election fraud when reports of an illegal election cell in President House were leaked to the media.
Khan had problems with both prime ministers who held power during his tenure, mainly because the elected governments made a pitch for greater powers and Khan invariably tried to frustrate them.
The source of friction was invariably the appointments to the top military and judicial offices, areas which both Benazir Bhutto and Nawaz Sharif tried but failed to get a handle on.
His admirers remember him as an honest man, but his detractors feel Khan used his official position to advance the careers of some relatives having questionable reputations.
Out of sight
Although Khan held several political offices during his career, including the country's top office, he never operated in a democratic setting and could not evolve into a politician.
This was evident when he went completely out of public view following his resignation as president in 1993.
Initially it was hoped that Khan might write a book detailing his version of the trials and tribulations that characterised some important stages of the country's history, but it did not happen.
Khan even shunned the media, thereby foreclosing any chance of a journalist getting him to explain some important events in which he either played an active role or to which he had been a witness.
He was not very popular in his native village of Ismailkhel in North-West Frontier Province,
He was buried in Peshawar, in accordance with his wishes.