By Christophe Pons
BBC News, Libreville
Africa's longest-serving head of state, Gabon's Omar Bongo Ondimba, 69, is seeking re-election.
The posters read: Bongo - I still want a bit more
He has ruled this oil-producing country since 1967 and won the country's only two previous multi-party elections, in 1993 and 1998.
He faces four challengers - with the candidate getting the most votes declared the winner.
Radical opposition leader Pierre Mamboundou, 59, head of the UPG (Union of Gabonese People) is seen as the most serious threat to Mr Bongo, followed by the independent Zacharie Myboto, 67, who has recently resigned after 20 with the ruling party.
The other candidates are Augustin Moussavou King of the little known Socialist Party, and Christian Serge Maroga, of the RDD (Rally of the Democrats).
With a fragmented opposition, the new electoral system, after 2003 constitutional changes removed the need for a winning candidate to get 50% of the votes, could benefit the ruling PDG (Democratic party of Gabon).
After 38 years under Omar Bongo's regime, the opposition is mainly campaigning for change and an end to corruption.
On the social front, Mr Mamboundou advocates a thorough reform of the health service, with free education for all, and benefits for single parents.
Similarly, fighting poverty and developing education feature as priorities in Mr Myboto's programme.
Not everyone has benefited from Gabon's stability and oil wealth
He pledges to promote "more equality and humanism where everyone will feel at home and able to express themselves freely".
In the presidential camp, the PDG and dozens of affiliated political parties claim that Mr Bongo's experience mean he is best placed to maintain peace and stability.
Mr Bongo's supporters are eager to stress that Gabon has not had a successful military coup in 45 years of independence, unlike many of its neighbours.
"At least we know him and it is better to vote for someone you know," one man said.
The president has based his strategy on an unprecedented use of political advertising coupled with the systematic distribution of gifts on the campaign trail.
Known as the "electoral franc", the distribution of money to parties, individuals and associations supporting the incumbent president led to several incidents over the sharing of the presidential presents.
Just ahead of the campaign, the president announced that the whole population of Gabon would not have to pay their electricity and water bills for November, saying this gesture was meant to alleviate poverty.
Pierre Mamboundou is running against Mr Bongo for a second time
The extensive use of high-tech advertising panels in Libreville glorifying Mr Bongo has illustrated the profound financial gap between the president's supporters and the other political parties.
The complete absence of electoral posters of the opposition candidates has also cast a shadow of bias over the campaign. Fifteen years after the legalisation of opposition parties, Gabon still has the feel of a one-party state.
On radio and television, the coverage of Mr Bongo's campaign dominates, although some reports are regularly broadcast on the activities of his challengers.
Complaints put to the National Council for Communication, a body accused of bias towards the president, received no answer.
The last days of the campaign have seen tensions rising.
The government shut the Omar Bongo University after a rally of students supporting Mr Mamboundou.
A ban on marches imposed in the last week of the campaign was challenged by UGP supporters who clashed with police forces in the centre of Libreville.
The whole campaign was marked by a climate of mutual distrust and suspicions.
Mr Bongo's wife (L) is helping the president (R) campaign
While the presidential camp accused the opposition of "inciting violence" by calling on its supporters to wear red, the opposition claims that massive electoral fraud is under way.
All previous presidential polls have been denounced as irregular by the opposition.
The first pluralist poll in 1993 was followed by bloody riots, amid accusations of fraud, when Mr Bongo officially won 51% of the vote.
In 1998, the head of state was re-elected with more than 66%, while Mr Mamboundou, who is now running for the second time, got 16%.
Observers say Mr Mamboundou's strong point is the fact that he never compromised with the ruling party.
This is seen as a performance and a sign of commitment in a country where many opposition leaders have been lured in the past into the highest power circles.
Most famously, Father Mba Abessole, the driving force of the radical opposition in the 1990s, joined the presidential side in 2002. He is currently one of the three deputy prime ministers in Mr Bongo's government.