Adnan Pachachi served as Iraqi foreign minister and ambassador to the UN before the Baathists seized power in a coup in 1968.
As a nationalist with a secular liberal outlook, who is believed to be favoured by the US State Department as a possible Iraqi leader, he has become an influential member of the Iraqi Governing Council.
Mr Pachachi led the Iraqi delegation to the UN Security Council in July 2003.
As a member of one of Iraq's elite Sunni families from the pre-Baath era, he is well known in Iraq.
Mr Pachachi, an octogenarian, is head of the Iraqi Independent Democrats and is seen as a possible unifying force amid Iraq's religious and ethnic factions.
He is well connected in the Gulf and spent his years of exile in Abu Dhabi, where he was an adviser to the government of the United Arab Emirates.