No Iranian official is better versed in western thinking than Iran's urbane new foreign minister, Mohammed Javad Zarif, a US-educated career diplomat, who is highly regarded by western officials and academics who have met him.
They view him as the ideal Iranian intermediary to ease tensions in the high-stakes dispute over Tehran's nuclear programme and to rebuild relations with the United States.
Mr Zarif helped draft a "grand bargain" proposal in 2003 that offered talks with the US on all the major issues dividing the two countries, including the nuclear file and the Arab-Israeli dispute.
That effort, which involved secret talks in Paris, Geneva and New York, was eventually spurned by the administration of then US president George W Bush.
Years earlier, as a junior diplomat, Mr Zarif was involved in negotiations to win the release of US hostages held by Iranian-backed gunmen in Lebanon.
In late 2001 he was instrumental in forging the compromises that led to the formation of a new government in Afghanistan after the US-led invasion toppled the Taliban regime following the September 11 attacks.
"He's a revolutionary but not an ideologue. He believes strongly in Iran's sovereignty and security but he's also someone who understands the West," said Hooman Majd, a New York-based Iranian-American author who knows Mr Zarif well. "He's charming, smart and has a great sense of humour. He's the best diplomat Iran has."
His appointment by Iran's moderate new president, Hassan Rouhani, was well received in the West, which was frustrated by eight years of grandstanding by Mr Rouhani's populist and pugnacious predecessor, Mahmoud Ahmadinejad.
There have been signals from Tehran that Mr Zarif, 54, will be given the additional role of leading the Iranian delegation in nuclear negotiations with six world powers which are expected to resume in October.
For the past decade the head of Iran's hardline supreme national security council has fronted the on-off nuclear talks.
Iran's outgoing chief nuclear negotiator, Saeed Jalili, is an uncompromising anti-western ideologue who ran for the presidency in June's elections but was trounced by Mr Rouhani.
Mr Zarif has promised a more moderate foreign policy while insisting that sanctions will not force Iran to compromise on its right to a peaceful nuclear programme.
Instead, he and Mr Rouhani say, Iran will offer more transparency on its atomic activities to prove these are not, as western powers suspect, aimed at developing a weapons capability.
"We want to show the world that there is no threat from Iran," Mr Zarif said on Thursday. "Nuclear weapons have no place in Iranian doctrine. Rather they are a threat to our national security. We are a powerful country and fundamentally do not need nuclear weapons."
Mr Rouhani and Mr Zarif are keenly aware they shoulder the burden of great expectations among ordinary Iranians. One message on Mr Zarif's Facebook page, which has 64,000 "fans", reads: "I hope you can fulfil the pledges of Dr Rouhani to restore proper ties based on mutual respect with the West, especially the US."
Another posting implores: "We want you and Mr Rouhani to become our heroes by solving the nuclear problems and sanctions."
Mr Zarif, fluent in English, spent much of his adult life in the US where his two children were born. He studied international relations at San Francisco State University before earning a doctorate in international law and policy at the University of Denver.
Between 2002 and 2007 he served as Iran's top representative at the United Nations in New York. Given that Iran has not had diplomatic relations with the US for more than 30 years, the UN job is a crucial one, almost equivalent to a cabinet post.
Mr Zarif's Washington contact book includes the US vice president Joe Biden, the defence secretary Chuck Hagel, and a who's who of US national security officials on both sides of the aisle.
"He has met with people at almost every level of the American administration and also the private American think-tank world and the academic world," said Gary Sick, an Iran expert at Columbia University in New York.
"So he knows American politics and he knows what is possible and what is not possible."
Sir Richard Dalton, a British former ambassador to Iran, said he believed Mr Zarif would "do an excellent job", although much would depend on how much flexibility he is given "by the system as a whole".
The framework and tenor of Iran's foreign and nuclear policy are set by Iran's hardline supreme leader, Ayatollah Ali Khamenei, who is viscerally mistrustful of the US.
However, the ayatollah may be grudgingly prepared to give Mr Rouhani, himself a former chief nuclear negotiator, the chance to explore whether an accommodation can be reached with Washington.
Mr Zarif, like Mr Rouhani, is "fully trusted" by the supreme leader, said Mr Majd, the author of The Ayatollahs' Democracy.
For the first time in years, both Iran and the US are ready to engage at the same time, experts say. But even an interim solution would require meaningful concessions by each side.
Tehran would have to significantly limit its uranium enrichment programme while Washington must accept some Iranian nuclear fuel production and offer a far better deal on easing sanctions than it had so far.
Mr Zarif confidently swatted aside hostile questioning at his confirmation hearing this month before a parliament dominated by hardliners. Several MPs accused him of being pro-West and alleged he had visited the US this spring to apply for a green card that would give him US citizenship.
Firmly denying the allegation, he said he had been in Tehran at the time, pushing his elderly mother's wheelchair. His robust 30-minute address to legislators was sprinkled with quotations from the Quran and respectful references to Mr Khamenei, which silenced the boisterous chamber.
"Today, the world needs moderation and the Islamic Republic of Iran, as a powerful country, can advance its foreign policy with moderation," Mr Zarif said recently.
"I very much hope that the Obama administration is listening and is capable of responding in kind," said Mr Sick, a former US National Security Council official. "There is an opening here, but it will remain open only if [US president Barack] Obama and western leaders are willing to stand up to the war-mongering rhetoric from some quarters [in the US]."
