For at least the last decade, diplomats and journalists lucky enough to be posted to the Cuban capital, Havana, have been mulling over one key question: what is going to happen after Fidel Castro has gone?
By Stephen Gibbs
Few observers have been able to read Fidel Castro like a book
They dwelled over various scenarios.
The most likely one was that the indefatigable leader would die in power. The least likely, that he would be overthrown by a counter-revolution or an internal coup.
Little time was spent considering what, in the end, has actually happened.
After nearly 50 years in which he has dominated almost everything in Cuba, the president appears to be going quietly, at a time of his choosing.
"The nature of his illness has been very fortunate for the government here" said one Western ambassador several months after Mr Castro was taken ill with a chronic intestinal ailment in July 2006.
What he meant is that the seriousness of Mr Castro's illness forced him to retire, but did not kill him.
The country was thus spared the shock of a sudden death - Fidel Castro's successors were given breathing space, and time to prepare for the future.
So what does that future hold?
The general assumption is that in the short term at least, change, if any, will be modest.
Firstly it must be remembered that Mr Castro is still with us.
Those close to Raul say he is very different from his brother
Although he is standing down as both president of the Council of State and commander-in-chief of the armed forces, he has made it clear that he will continue to comment on national events via the state-controlled media.
His presence, albeit in the background, makes it highly unlikely that his successor will take Cuba on a radically different path.
That successor is most likely to be his younger brother, Raul.
Keeping it in the family
For the past 19 months, the 76-year-old, as acting president, has been quietly consolidating his power in Cuba.
The army, which he leads, has an ever-increasing role in running the country.
If you are a foreign investor hoping to partake in a major project in Cuba, you await permission not from the ministry of foreign investments, but from the army.
Those close to Raul say he is a very different man from his brother.
He dotes on his family, he keeps regular office hours, he likes a joke, and has developed a suspicion of ideology.
Raul has publicly expressed his exasperation with some of the inefficiencies of the Cuban economy, and has already instigated some limited reforms, particularly limited de-centralisation of the agriculture sector.
As president, he might feel the moment has come to start extending those reforms.
Perhaps he will also want to demonstrate his willingness to listen to, and act upon current public concerns.
Chief amongst these is the complaint by Cubans that their state salaries of around $15 a month are blatantly insufficient, and force almost everyone to turn to the black market. Younger Cubans also are openly frustrated about the fact that they are not allowed to travel without often-denied government permission, or freely access the internet.
Doing something about any one of these complaints would boost Raul Castro's popularity, at the risk of raising expectations.
It is of course possible, although unlikely, that Raul will not be the next president of Cuba.
Fidel Castro's resignation letter explicitly did not mention a successor, and he has repeatedly spoken of handing over power to a "younger generation".
If Raul is not elected president by the National Assembly on Sunday it opens up some interesting possibilities.
Carlos Lage Davila is a leading contender for the Cuban presidency
Although Cuban government officials insist that there is no shortage of suitable successors to Fidel, they tend not to name anyone.
Instead they say that the Communist Party will fulfil his vision.
But on Sunday it is likely to be revealed who the Cuban leadership believes is best placed to succeed Fidel Castro in the longer term.
A likely candidate is the de-facto economics minister, Vice-President Carlos Lage Davila, who is seen as both a trustworthy communist by hardliners and a pragmatist by reformers.
Another possibility is Felipe Perez Roque, the foreign minister long seen as one of Fidel Castro's most loyal admirers in the government.
Whoever it is, it will be a reminder to Cubans that after half a century, one day they will be led by a man who is not called Castro.
Stephen Gibbs is the former BBC correspondent in Cuba. He returned to London in August.