How will the election be conducted?
Italy has a bicameral legislature and a voting system which even many Italians say they find confusing.
Voters will be electing 315 members of the Senate, and 630 members of the Chamber of Deputies. Both houses hold the same powers, although the Senate is referred to as the upper house.
Under the country's closed-list proportional representation system, each party submits ranked lists of its candidates, and is awarded seats according to the proportion of votes won -- provided it passes a minimum threshold of support.
Seats in the Chamber of Deputies are on a national basis, while seats in the senate are allocated on a regional one.
The party with the most votes are awarded a premium of bonus seats to give them a working majority.
The prime minister needs the support of both houses to govern.
Who is likely to be the next prime minister?
On current polling, Bersani's bloc looks the likely victor in the Chamber of Deputies. But even if he maintains his lead in polls, he could fall short of winning the Senate, because of the rules distributing seats in that house on a regional basis.
Crucial to victory in the Senate is winning the region of Lombardy, the industrial powerhouse of the north of Italy which generates a fifth of the country's wealth and is a traditional support base for Berlusconi. Often compared to the U.S. state of Ohio for the "kingmaker" role it plays in elections, Lombardy has more Senate seats than any other region.
If no bloc succeeds in controlling both houses, the horse-trading begins in search of a broader coalition.
Walston said that a coalition government between the blocs led by Bersani and Monti seemed "almost inevitable," barring something "peculiar" happening in the final stages of the election campaign.
Berlusconi, he predicted, would "get enough votes to cause trouble."
What are the main issues?
There's only really one issue on the agenda at this election.
The eurozone's third largest economy is hurting, with unemployment surpassing 11% -- and hitting 37% for young people.
Voters are weighing the question of whether to continue taking Monti's bitter medicine of higher taxation and austerity measures, while a contentious property tax is also proving a subject of vexed debate.
Walston said the dilemma facing Italians was deciding between "who's going to look after the country better, or who's going to look after my pocket better."
He said it appeared voters held far greater confidence in the ability of Monti and Bersani to fix the economy, while those swayed by appeals to their own finances may be more likely to support Berlusconi.
But he said it appeared that few undecided voters had any faith in Berlusconi's ability to follow through on his pledges, including a recent promise to reverse the property tax.
What are the ramifications of the election for Europe and the wider world?
Improving the fortunes of the world's eighth largest economy is in the interests of Europe, and in turn the global economy.
Italy's woes have alarmed foreign investors. However, financial commentator Nicholas Spiro, managing director of consultancy Spiro Sovereign Strategy, says the European Central Bank's bond-buying program has gone a long way to mitigating investors' concerns about the instability of Italian politics.
Why is political instability so endemic to Italy?
Italy has had more than 60 governments since World War II -- in large part as a by-product of a system designed to prevent the rise of another dictator.