BBC News Online looks at key questions facing Serbia after the death of Prime Minister Zoran Djindjic.
How will Djindjic be remembered?
He was most often described as a pragmatist. He was not much loved by Serbian voters because he took difficult decisions - his economic reforms caused financial hardship. He did not present himself as a saint. "If you want morality, go to church," he once said.
When necessary he did deals with shady people. It is alleged that he struck a deal with the special police in order to topple Yugoslav President Slobodan Milosevic, which he then failed to honour.
What will his death mean for Serbian politics?
The country is faced with a political power vacuum. It has no president, because elections have twice failed to produce a result. Now it has no prime minister either.
Mr Djindjic has no obvious successor, and whoever takes over from him may find it difficult to hold together the fractious governing coalition of more than 10 parties, which Mr Djindjic has manipulated with consummate skill.
Correspondents expect a struggle for the leadership of Mr Djindjic's Democratic Party, as well as a struggle to head the government.
However, they say economic and political reforms are likely to continue because Serbia is currently in no position to defy the United States and the European Union.
The question is how quickly and efficiently the reforms will be pursued.
Who are the politicians to watch?
The former Yugoslav President, Vojislav Kostunica, could potentially make a comeback, particularly if Mr Djindjic's departure results in a general election.
However, he and his Democratic Party of Serbia may lack the coalition-building skills needed to achieve and maintain power.
From within Mr Djindjic's party, Zoran Zivkovic, formerly Yugoslavia's minister of police, is a possible contender for the premiership. Prior to Mr Djindjic's death, he was due to become Serbia's armed forces minister.
Another politician with strong prospects is a Serbian deputy prime minister, Nebojsa Covic, from the Democratic Alternative Party.
What are the implications of Mr Djindjic's death for regional politics?
Serbia is likely to concentrate on its own internal affairs in the immediate future.
This could mean a delay in the formation of the new government of Serbia and Montenegro - the state formed last month to replace Yugoslavia.
Planned talks on co-operation between Belgrade and Kosovo, which came under UN administration after Nato's conflict with Yugoslavia in 1999, are also likely to be postponed.