Iranians head to the polls for the country's twelfth presidential election on Friday in a contest likely to determine whether Tehran's re-engagement with the world stalls or quickens.
Four candidates are still in contention, but analysts see incumbent President Hassan Rouhani and challenger Ebrahim Raisi as the favourites.
If that expectation is met, then voters will be deciding whether Rouhani's policy of greater engagement with the West continues, or whether it could stall under Raisi if the conservative cleric becomes president.
Iran's Ministry of the Interior says 56.41 million voters are eligible to cast ballots on Friday. Final results are expected by Sunday.
The incumbent President Hassan Rouhani won the 2013 presidential election by a landslide. He leads in the opinion polls ahead of Friday's vote.
The 68-year-old cleric has maintained his alliance of moderates and reformists, despite economic setbacks for a country still recovering from years of sanctions.
Rouhani signed a landmark nuclear deal with world powers in 2015 that lifted many sanctions. But his critics say he has failed to produce the jobs, growth and foreign investment he said would follow.
Rouhani's strongest challenger appears to be conservative cleric Ebrahim Raisi, 56, who says Iran does not need foreign help. Raisi has promised a return to the values of the 1979 Islamic Revolution.
Raisi has spent decades in powerful judicial and backroom positions, including as Iran's prosecutor-general. But he has little direct political experience.
A close ally of Supreme Leader Ayatollah Ali Khamenei, Raisi is also thought to be in line to become supreme leader in the future.
One of the minor candidates on Friday is 71-year-old Mostafa Mirsalim, a member of the Islamic Coalition Party, one of the oldest conservative factions in predominantly Shia Iran.
From 1981 to 1989, Mirsalim served as a senior adviser to Ayatollah Khamenei, who was president at the time. Mirsalim was the minister of culture in the 1990s, when he oversaw increasing censorship, the banning of Western films and music, and the closure of opposition newspapers.
The other minor candidate is Mostafa Hashemitaba, 71, a lesser known political figure, who is a member of the pro-reform Construction Party.
Hashemitaba has served in several capacities, first as industry minister in the early 1980s and later as a vice president. He was head of Iran's National Olympic Committee in the early 2000s. And he supported the closure of newspapers and a crackdown on dissidents in the early 2000s.
Hashemitaba took part in the 2001 presidential election, winning just 28,000 of the 28 millions votes cast.