Ashraf Ghani is an intense, intellectual high-achiever with a famous temper, his rule would seldom be dull if he becomes president.
Mr Ghani, 65, was a career academic and economist who left Afghanistan in 1977 and returned 24 years later to pursue his dream of rebuilding the country.
He worked with the World Bank from 1991, becoming an expert on the Russian coal industry, and finally moved back to Kabul as a senior UN special adviser soon after the Taliban were routed in late 2001.
In the heady days that followed, he was a key architect of the interim government and became a powerful finance minister under Hamid Karzai from 2002 to 2004, campaigning hard against burgeoning corruption.
Renowned for his energy, Mr Ghani introduced a new currency, set up a tax system, encouraged wealthy expatriate Afghans to return home, and cajoled donors as the country emerged from the austere Taliban era.
* Agence France-Presse