By Paul Reynolds
World Affairs Correspondent, BBC News website
Caspar Weinberger was the powerhouse behind the huge expansion of US military strength during the presidency of Ronald Reagan.
A confident Cold War warrior, he was defence secretary from the start of Reagan's presidency in January 1981 until he resigned in November 1987.
Weinberger served former US Presidents Nixon and Reagan
He got Congress to approve major defence spending increases that financed the modernisation of US forces with new missiles - including the Trident D5 - and aircraft.
He also championed the space defence system nicknamed Star Wars, though funding was gradually decreased as doubts about the system grew.
His record however was marred when, after leaving office, he was indicted in the Iran-Contra affair in which arms were illegally sold to Iran and the money used to help the Contra guerrillas fighting against the Sandinista government of Nicaragua.
He always said he had opposed the sales but was charged with having lied to Congress about them. President George Bush Sr pardoned him in 1992.
A small, wiry man with a wry smile, Weinberger's manner was one of a steely determination to build up American power and to use it in US interests and in the interest of US allies.
His role was to support with military hardware Ronald Reagan's strategic vision of standing up to the Soviet Union and of possible bringing about its collapse.
The vision was eventually accomplished, though history might argue as to whether the economic failures of communism were not just as responsible.
He was an Anglophile - his mother's parents came from England; as part of the American melting pot, his paternal grandfather was from a Jewish family in Bohemia - and during the Falklands war in 1982, he immediately and effectively sided with the UK.
He provided key weapons systems and supplies, notably the Sidewinder missile, to the British task force.
Former British Prime Minister Margaret Thatcher later said that without the Sidewinder "supplied to us by US Defence Minister Caspar Weinberger, we could never have got back the Falklands."
He disapproved of the efforts of the US Secretary of State Alexander Haig who in the early stages shuttled between London and Buenos Aires seeking a diplomatic solution. In 1988 he was awarded an honorary knighthood for an "outstanding and invaluable" contribution to military cooperation between the UK and the US.
"Cap" Weinberger, as he was known, and sometimes "Cap the Knife" when he waded into bureaucracy, thoroughly approved of Ronald Reagan's soul mate Margaret Thatcher and saw in her, as much as his president did, a key ally against the Soviet Union.
Among military operations on his watch were the invasion of Grenada in 1982 and the air attack on Libya in 1986.
The American role in a multi-national force in Lebanon led to the deaths of 241 US marines in Beirut in October 1983.
Caspar Weinberger rose through the political ranks alongside Reagan in California.
Weinberger was regarded as one of Reagan's closest allies
He served under Governor Reagan as finance director and the two became political allies.
Later he went to Washington as Secretary of Health, Education and Welfare under President Nixon.
I went to interview him in California in 1979 when it became clear that Reagan would run for the presidency in 1980 and that he would play an important role if Reagan won.
In the clipped tones that later became a familiar counterpoint to the flowing sentences of his boss, he was absolutely clear about the direction in which a Reagan presidency would go.
Weinberger was not a man who expressed any doubts.
And just about everything he said would happen in that interview - the growth and use of US power above all - came to pass.