Egyptians vote on Saturday in a referendum on changes to the constitution that would pave the way for new parliamentary and presidential elections within six months.
Following the uprising that forced President Hosni Mubarak to step down in February, the referendum is being seen as a major test for Egypt's transition to democracy after 30 years of authoritarian rule. But critics are pushing for a "no" vote, arguing a more radical rethink is needed and that the ruling military council is rushing the process.
What is the referendum about?
Egypt's military council suspended the constitution and dissolved parliament last month, meeting demands made by the opposition movement that ousted Mr Mubarak.
The Egyptian constitution had been written with built-in guarantees to keep Mr Mubarak and his political party in power. A committee of judicial experts was appointed to recommend the changes needed to ensure free and fair elections in the future.
Voters are now being asked whether they approve of the changes.
What is being proposed?
Under the proposed amendments to the constitution, the future president would only be allowed to serve two four-year terms, instead of unlimited six-year periods. He or she would also be obliged to appoint a deputy, something Mr Mubarak avoided until his last days in office.
Other amendments would make it easier for individuals to qualify to run as a presidential candidate and re-instate judicial supervision for elections. It would also be more difficult for any leader to maintain the state of emergency.
However the scholars that drafted the changes decided to put off steps limiting presidential powers until after the elections. They suggested the next parliament should form a committee to rewrite the constitution entirely.
Why is the referendum proving controversial?
While Egypt's political opposition has long demanded constitutional reforms, many leading figures complain these changes were drawn up in haste and do not go far enough. The amendments were drafted in just 10 days and offered to the public for discussion for only three weeks.
Young activists who led the 18 days of popular protests have called for a "no" vote in the referendum and are planning new demonstrations on Friday.
Potential presidential candidates including Arab League Secretary General Amr Moussa, and former UN nuclear watchdog chief Mohamed ElBaradei want a new constitution to be drawn up from scratch before any elections are held.
Meanwhile, the two largest political forces in the country - the former ruling National Democratic Party and the Muslim Brotherhood - are encouraging members to vote in favour of the amendments, warning of the dangers of a legislative vacuum.
They are most likely to benefit from early elections as dozens of smaller parties set up following the uprising have yet to fully organise themselves.
What happens if there is a "no" vote?
If the proposed changes are rejected, the amended constitution will be scrapped and a new one drawn up from scratch. Security sources say this would delay the parliamentary and presidential elections to December and early 2012.
In the meantime, Egypt's military council would issue a constitutional decree as a temporary measure.
Analysts suggest the army is eager to keep its early time frame for elections, as it does not want to be tainted by perceived failure to solve the country's manifold problems.
Will this referendum be free and fair?
Whatever the outcome, the referendum could give Egyptians their first experience of a free vote in decades. Under Mr Mubarak's rule, elections were marred by vote-rigging and fraud.
Any Egyptian over the age of 18, holding a national identity card is eligible to vote: This gives a total electorate of about 40 million people.
Polling stations are expected to open between 0800 and 1900 local time. They will be secured by police and supervised by 16,000 members of the judiciary.
Civil society groups and the media have been invited to monitor proceedings.