Bolivia has suffered chronic political instability
The people of South America's poorest nation go to the polls on Sunday 18 December to elect a new president, parliament and departmental prefects.
Eight candidates are standing for president, but only Evo Morales, of the Movement Toward Socialism (Mas), and former president Jorge "Tuto" Quiroga are thought to have a real chance of winning.
Mr Morales, the coca-growers' leader and an Aymara Indian, has a slight lead over his conservative rival. If elected he would become Bolivia's first indigenous president.
Q: What is at stake?
This is a key election for Bolivia. Despite having the second largest natural gas reserves in the region, the country is wracked by poverty. Nearly 70% of the population live below the poverty line and 14.4% live on less than $1 a day.
Bolivia has had five presidents in four years and faces deep economic, ethnic and regional divisions. The political system is still dominated by a small, wealthy elite, with the majority indigenous population largely excluded from power.
Since the last presidential election, disputes over the conditions under which foreign oil companies operate, the export of natural gas and the cultivation of coca have led to outbreaks of violence that have paralysed the country and polarised its people.
Q: Who will be voting?
About 3.7 million people are registered to vote, out of a total population of about 9.1 million, according to current United Nations population figures.
About 30% of the electorate are Quechua-speaking and 25% are Aymara.
Voters will elect the president, 27 senators, 130 deputies and nine departmental prefects.
Voting is compulsory for all Bolivians over the age of 18. Bolivians abroad will not be able to take part.
The polls will open at 0800 local time and will close at 1600.
Q: Who are the main candidates?
Evo Morales, 46, has been criticised by the USA for his closeness to the left-wing governments of Fidel Castro in Cuba and President Hugo Chavez in Venezuela.
He has also come under fire for his plans to legalise the production and consumption of coca leaves, a traditional part of Indian life. He has said he will replace the "zero coca" policy with a "zero drug-trafficking" policy.
An avowed "anti-neoliberal", he has pledged to increase state control over the country's oil and gas reserves by buying back foreign-owned refineries.
He has also pledged to change the constitution through a Constituent Assembly to improve the rights of Bolivia's indigenous majority.
In a nod to them he has said his government will be guided by the Aymara principles of "ama sua" (do not steal), "ama llulla" (do not lie), "ama kella" (do not be lazy) and "ama llunku" (do not be servile).
The other main candidate, Jorge Quiroga, 45, is a US-educated engineer who served as president from July 2001 to August 2002 after President Hugo Banzer resigned due to ill health.
A former consultant for the World Bank, he advocates raising the export price for Bolivia's gas and channelling the funds into social programmes aimed at the poor.
His political campaign has been fought on a programme of creating more jobs by building up the productive sector and broadening the scope of free trade agreements, making health care more accessible, and implementing a "zero coca" policy in the coca-growing regions.
Q: Who are their supporters?
Some observers have described the presidential race between Mr Morales and Mr Quiroga as a wider face-off between the "cambas", as people from Santa Cruz are known, and the "collas", the Indians of La Paz and the highlands.
Mr Morales's support comes largely from the western Cochabamba and Oruro departments and the township of El Alto above La Paz, where many rural Aymara come looking for work.
Mr Quiroga's support is strongest in the wealthy eastern department of Santa Cruz, where most of the gas reserves and large-scale modern agribusinesses are found. He also has a strong following in the provinces of Beni, Chuquisaca, Pando, Potosi and Tarija.
A large portion of the electorate is split between these two regions, with about 22% of registered voters living in Santa Cruz and about the same number living in the city of La Paz and the nearby town of El Alto.
Q: Who is likely to win?
According to the latest opinion polls, Mr Morales has a five point lead over Mr Quiroga but neither candidate is likely to obtain the 51% absolute majority needed to win outright.
Q: What happens if there is no clear winner?
Under Bolivia's constitution, if no candidate wins an absolute majority, the Congress elected on Sunday, which will be sworn in on 16 January, will choose between the two leading contenders. Interim President Eduardo Rodriguez's 180-day term ends on 23 January.
In the last presidential elections in June 2002, Mr Morales came a close second to Gonzalo Sanchez de Lozada in the election but was roundly defeated in the Congressional vote by 84 to 43.
Some observers predict that Mr Morales will win the election but then fail to secure enough votes in Congress to become president.
If that happens there would be little chance of an end to Bolivia's political instability.
BBC Monitoring selects and translates news from radio, television, press, news agencies and the Internet from 150 countries in more than 70 languages. It is based in Caversham, UK, and has several bureaus abroad.